identify the transfer function of a highpass filter with a passband gain of 100 and a cutoff frequency of 30 rad/s.

The demonstration of apparent movement provides support for the gestalt approach because it emphasizes the role of perceptual organization and the brain's tendency to perceive patterns and wholes rather than isolated elements.

The gestalt approach to psychology focuses on how humans perceive and interpret the world around them. It suggests that perception is not solely based on the sum of individual sensory stimuli but is influenced by the organization and structure of those stimuli. According to gestalt principles, our brains naturally seek to perceive objects and scenes as meaningful, organized wholes rather than unrelated parts.

One phenomenon that supports the gestalt approach is apparent movement, also known as the phi phenomenon. Apparent movement refers to the perception of motion when a sequence of static images is presented in rapid succession. For example, when a series of still images is projected in quick succession, our brains perceive it as continuous motion, such as in movies or animations.

The gestalt approach argues that apparent movement occurs because our brains fill in the missing information between the static images and organize them into a coherent pattern of motion. Instead of perceiving individual frames as separate entities, we perceive them as a unified and continuous whole.

This demonstration of apparent movement supports the gestalt approach by highlighting our brain's innate tendency to organize sensory input into meaningful patterns and wholes. Rather than perceiving isolated frames, we perceive a continuous motion based on the principles of closure, continuity, and similarity, which are fundamental concepts within the gestalt framework.

In summary, the demonstration of apparent movement provides support for the gestalt approach because it showcases our brain's inclination to organize sensory stimuli into coherent patterns and wholes, aligning with the fundamental principles of perceptual organization proposed by the gestalt psychologists.

Learn more about gestalt approach: https://brainly.com/question/13650345

#SPJ11

Graphing the Relationship Between Temperature and Vapor Pressure. the graph generated using equation 1 illustrates the relationship between temperature and vapor pressure.

The graph illustrates the relationship between temperature and vapor pressure, with temperature represented on the x-axis and vapor pressure on the y-axis. The equation used to generate the graph is given by:

esat = A * exp(-erp(TC))

In this equation, "esat" represents the saturation vapor pressure, "A" is a constant, "exp" denotes the exponential function, "erp" is another constant, and "TC" stands for temperature in degrees Celsius.

To create the graph, we will plot a range of temperatures from -30 to 50 °C on the x-axis and calculate the corresponding vapor pressures using the given equation. By associating each temperature value with its respective vapor pressure, we can visualize the relationship between the two variables.

The graph indicates that as temperature increases, vapor pressure also tends to rise. This positive correlation is commonly observed in various contexts, such as the behavior of water vapor in the atmosphere or the boiling point of liquids.

In more detail, the equation suggests that the vapor pressure (esat) is influenced by the temperature (TC) through the exponential function. The constant "erp" determines the rate at which the vapor pressure changes in response to temperature variations. The parameter "A" serves as a scaling factor, adjusting the overall magnitude of the vapor pressure values.

By plotting the calculated values on the graph, we can visually analyze the relationship. The x-axis, representing temperature, will span from -30 to 50 °C, allowing us to observe the behavior of vapor pressure across this temperature range. The y-axis, representing vapor pressure, will display the corresponding values calculated using the given equation.

The resulting graph will provide a clear representation of how vapor pressure varies with temperature, highlighting the trend and any potential patterns that emerge. This visualization can be beneficial in understanding the thermodynamic properties of substances or predicting changes in vapor pressure under different temperature conditions.

In conclusion, the graph generated using equation 1 illustrates the relationship between temperature and vapor pressure. The equation incorporates constants A and erp, while esat represents the saturation vapor pressure. The resulting graph demonstrates how vapor pressure changes with temperature, showcasing the positive correlation between the two variables. This graphical representation facilitates the analysis of vapor pressure behavior across a given temperature range, providing valuable insights into the thermodynamic properties of substances.

Learn more about Graphing here

https://brainly.com/question/29332221

#SPJ11

Both Technicians A and B are correct in their statements. Technician A highlights the importance of being able to research and apply technical information in today's automotive industry.

With advancements in technology, vehicles are becoming increasingly complex, and a technician's ability to access and utilize information from various sources, such as online databases and technical forums, is crucial for performing maintenance and repair activities effectively and efficiently.

Technicians need to have a good understanding of the latest technologies, diagnostic tools, and repair procedures to keep up with the changing demands of the industry.

Technician B, on the other hand, emphasizes the value of the owner's manual as a source of information. The owner's manual contains important details about the vehicle, including specifications, operating instructions, maintenance schedules, and troubleshooting tips. This information can be invaluable for both the owner and the technician in terms of understanding the vehicle's features and ensuring proper maintenance and repair. The owner's manual can also provide useful information for technicians in diagnosing and repairing problems.

In conclusion, both technicians are correct, and their statements complement each other. A skilled technician must have the ability to access and apply technical information from various sources, including the owner's manual, to perform maintenance and repair activities effectively and efficiently.

To know more about technology:

https://brainly.com/question/9171028

#SPJ4

Normal fuel crossfeed system operation in multiengine aircraft allows for fuel transfer between engine fuel tanks to maintain balanced fuel distribution and prevent fuel starvation.

Ensure Proper Configuration: The fuel crossfeed system is typically operated during normal flight conditions when the fuel imbalance reaches a predetermined threshold.

Activate Crossfeed Valve: The crossfeed valve, located in the cockpit, is selected to the "open" position. This allows fuel to be transferred from one engine's fuel tank to the other.

Monitor Fuel Gauges: Pilots monitor the fuel quantity gauges to ensure the balanced transfer of fuel between the tanks. The goal is to equalize the fuel levels or maintain a desired fuel imbalance as per aircraft limitations.

Maintain Awareness: Pilots remain aware of any changes in fuel imbalance and adjust the crossfeed valve as needed to maintain proper fuel distribution.

Fuel Management: Pilots may also manage fuel consumption and crossfeed operation to optimize performance and efficiency during different phases of flight.

Deactivate Crossfeed: Once the desired fuel balance is achieved or during specific flight conditions, the crossfeed valve is returned to the "closed" position to isolate the fuel tanks and allow independent operation of each engine.

Proper operation of the fuel crossfeed system ensures optimal fuel management and contributes to the safety and efficiency of multiengine aircraft during normal flight operations.

To know about Normal fuel visit:

https://brainly.com/question/31562307

#SPJ11

a) Without the sign: 53.79 hp.

b) With the sign: The sign does not affect the drag force acting on the truck, so the horsepower required would still be 53.79 hp.

To estimate the horsepower required to drive the truck at 50 miles/hour, we can use the following equation:

Power (hp) = (Drag Force (lb) * Velocity (mph)) / 375

The drag force acting on the truck can be calculated using the drag coefficient and the frontal area of the truck:

Drag Force (lb) = (1/2) * Density of Air (lb/ft^3) * Velocity (mph)^2 * Drag Coefficient * Frontal Area (ft^2)

We can assume the density of air to be approximately 0.00237 lb/ft^3 at a temperature of 70°F and pressure of 1 atm.

Plugging in the values given in the question, we get:

Drag Force (lb) = (1/2) * 0.00237 * 50^2 * 0.83 * (6 ft * 7 ft) = 647.24 lb

Plugging this value into the equation for power, we get:

Power (hp) = (647.24 lb * 50 mph) / 375 = 53.79 hp

Learn more about horsepower, here https://brainly.com/question/12260337

#SPJ4

Answer:

gdyc ddxtfvytg4dgtfxdwcftcd3rcby

If the crankshaft end play is out of specifications, check for:

Thrust Bearings

Main Bearings

Crankshaft

Crankshaft Thrust Washers

Engine Block

To understand the crankshaft when it is out of specifications, check for:

Thrust Bearings: Check the condition of the thrust bearings, which are located at the front and/or rear of the engine block. Excessive wear or damage to the thrust bearings can contribute to increased crankshaft end play.

Main Bearings: Inspect the main bearings, which support the crankshaft within the engine block. Worn or damaged main bearings can cause excessive movement of the crankshaft.

Crankshaft: Check the crankshaft itself for any signs of damage, such as scoring or bending. A damaged crankshaft may not sit properly within the bearings, leading to increased end play.

Crankshaft Thrust Washers: Some engines use thrust washers to control the end play of the crankshaft. Inspect these washers for wear, damage, or improper installation.

Engine Block: Check the engine block for any signs of damage or distortion that may affect the alignment and support of the crankshaft.

To learn more about Crankshaft, refer:

https://brainly.com/question/31841425

#SPJ4

Items like gloves, safety glasses, shoes, earplugs or muffs, hard helmets, respirators, or coveralls, vests, and full body suits are examples of personal protection equipment.

Wearing a safety helmet when using a power tool, donning the proper safety gear when dealing with chemicals, and taking all necessary measures when operating machinery are examples of the proper use of any equipment used to safeguard their health and the health of their coworkers.

Gloves, safety goggles, shoes, earplugs, respirators, hard hats, coveralls, vests, and full body suits are examples of personal protection equipment.

Healthcare Facilities Using PPE:

Gloves safeguard the hands; gowns or aprons defend the skin or clothing; masks and respirators screen the mouth and nose; goggles guard the eyes; and face shields cover the complete face.

To learn more about personal protection equipment refer to:

https://brainly.com/question/13720623

#SPJ1

Answer: True

Explanation:

Structural engineering is simply referred to as a branch of civil engineering, and they help in the designing of structures like buildings, dams, tunnels, bridges, tunnels, etc. Structural engineers typically work as consultants.

Wireless sensor networks are used by structural engineers to monitor the condition of dams and bridges. Wireless sensor network refers are dedicated sensors that are used in monitoring the physical conditions of the bridges and to know if they're still in good conditions.

Answer:

a) 4 hectómetros cuadrados equivalen a 400 decámetros cuadrados.

b) 21345 centímetros cuadrados equivalen a 2,135 metros cuadrados.

c) 0,592 kilómetros cuadrados equivalen a 592000 metros cuadrados.

d) 0,102 metros cuadrados equivalen a 1020 centímetros cuadrados.  

e) 23911 kilómetros cuadrados equivalen 2391100 hectómetros cuadrados.

Explanation:

a) 4 hectómetros cuadrados a decámetros cuadrados:

Según las unidades de área y sus escalas utilizadas por el Sistema Internacional de Pesos y Medidas, un hectómetro cuadrado equivale a 100 decámetros cuadradps. Entonces, obtenemos el dato equivalente por la siguiente regla de tres simple:

\(x = 4\,Hm^{2}\times\frac{100\,Dm^{2}}{1\,Hm^{2}}\)

\(x = 400\,Dm^{2}\)

4 hectómetros cuadrados equivalen a 400 decámetros cuadrados.

b) 21345 centímetros cuadrados a metros cuadrados:

Según las unidades de área y sus escalas utilizadas por el Sistema Internacional de Pesos y Medidas, un metro cuadrado equivale a 10000 centímetros cuadrados. Entonces, obtenemos el dato equivalente por la siguiente regla de tres simple:

\(x = 21345\,cm^{2}\times \frac{1\,m^{2}}{10000\,cm^{2}}\)

\(x = 2,135\,m^{2}\)

21345 centímetros cuadrados equivalen a 2,135 metros cuadrados.

c) 0,592 kilómetros cuadrados a metros cuadrados:

Según las unidades de área y sus escalas utilizadas por el Sistema Internacional de Pesos y Medidas, un kilómetro cuadrado equivale a 1000000 metros cuadrados. Entonces, obtenemos el dato equivalente por la siguiente regla de tres simple:

\(x = 0,592\,km^{2}\times \frac{1000000\,m^{2}}{1\,km^{2}}\)

\(x = 592000\,m^{2}\)

0,592 kilómetros cuadrados equivalen a 592000 metros cuadrados.

d) 0,102 metros cuadrados a centímetros cuadrados:

Según las unidades de área y sus escalas utilizadas por el Sistema Internacional de Pesos y Medidas, un metro cuadrado equivale a 10000 centímetros cuadrados. Entonces, obtenemos el dato equivalente por la siguiente regla de tres simple:

\(x = 0,102\,m^{2}\times \frac{10000\,cm^{2}}{1\,m^{2}}\)

\(x = 1020\,cm^{2}\)

0,102 metros cuadrados equivalen a 1020 centímetros cuadrados.

e) 23911 kilómetros cuadrados a hectómetros cuadrados:

Según las unidades de área y sus escalas utilizadas por el Sistema Internacional de Pesos y Medidas, un kilómetro cuadrado equivale a 100 hectómetros cuadrados. Entonces, obtenemos el dato equivalente por la siguiente regla de tres simple:

\(x = 23911\,km^{2}\times \frac{100\,Hm^{2}}{1\,km^{2}}\)

\(x = 2391100\,Hm^{2}\)

23911 kilómetros cuadrados equivalen 2391100 hectómetros cuadrados.

Answer:

Motor Vehicles, Mechanized Equipment, and Marine Operations ... These rules apply to the following types of earthmoving equipment: scrapers, loaders, ... which shall be operated as needed when the machine is moving in either direction

Note that the force on the disc is 38700 Nand the torque required to maintain the disc in the vertical position is 65550 N m.

Force = mass * acceleration due to gravity

= (volume * density) * acceleration due to gravity

= (πr² * height * density) * acceleration due to gravity

= (π * (3/2 m)² * 4 m * 1000 kg/m³) * 9.8 m/s²

Force = 38700 N

Torque = force * distance

= 38700 N * (3/2 m)

Torque = 65550 N m

Learn more about force at:

https://brainly.com/question/25239010

#SPJ1

Answer:

The voltage input to the inverting terminal is 60μV

Explanation:

Given;

open-loop gain, A = 150,000

output voltage, V₀ = 15 V

voltage at the inverting input, \(V_n\) = −40 μV = 40 x 10⁻⁶ V

The relationship between output voltage and voltage at the inverting input is given as;

\(V_o = A(V_p -V_n)\\\\15 = 150,000(V_p -(-40*10^{-6}))\\\\15 = 150,000 (V_p +40*10^{-6}) \\\\V_p +40*10^{-6} = \frac{15}{150,000} \\\\V_p + 40*10^{-6} = 1 *10^{-4}\\\\V_p + 40*10^{-6} = 100 *10^{-6}\\\\V_p = 100 *10^{-6} - 40*10^{-6}\\\\V_p = 60 *10^{-6}\\\\V_p = 60 \ \mu V\)

Therefore, the voltage input to the inverting terminal is 60μV

The average number of aircraft on the runway at the airport is approximately 12. The correct option is B

Since the average time spent between leaving the gate and taking off is 4 minutes, and an aircraft takes off every 0.67 minutes, we can conclude that the average number of aircraft on the runway during this time is 4 minutes / 0.67 minutes per take-off = 5.97 aircraft.

Similarly, the average number of aircraft on the runway during the time between landing and reaching their gate is also 5.97 aircraft.

Therefore, the average number of aircraft on the runway at the airport is the sum of these two values:

Average number of aircraft on the runway = 5.97 + 5.97

= 11.94

= 12 approximately

Learn more about average on

https://brainly.com/question/20118982

#SPJ4

The true power is obtained as 70.7 VA.

We define the power a the rate of doing work, we know that the power in a circuit is the product of the current and the voltage. In this case, we want to find the true power thus we have to involve the use of the phase shift in degrees.

Thus;

True power = PcosΦ

P =  100 VA

Φ = 45 degrees

True power =  100 VA * cos 45 degrees

True power = 70.7 VA

Learn more about power in a circuit:https://brainly.com/question/2933971

#SPJ1

The aphorism is often used to emphasize the importance of a proactive approach to transitioning to renewable energy.

While the Stone Age did not end because of a lack of stones, the transition to renewable energy could be stalled if we are not proactive in our efforts. The aphorism serves to remind us that the transition cannot be put off indefinitely, and that it is important to take action now in order to ensure a successful transition.

Additionally, the aphorism highlights the need for an all-encompassing approach to the transition, as opposed to a piecemeal approach, in order to ensure that all aspects of the transition are taken into account.

Learn more about renewable energy:

https://brainly.com/question/79953

#SPJ11

The relation between g and f is that g is a function that results from applying certain transformations to f. g can be expressed in terms of f by using the appropriate mathematical operations.

The given problem statement involves defining the function g as a transformation of the function f, with different variations of g for each f.

In general, a transformation from f to g involves performing some operation on the output of f to produce the output of g.

(a) For each variation of g, the transformations from f to g in English can be described as follows:

g1 takes the output of f and multiplies it by 2.

g2 takes the output of f and squares it.

g3 takes the output of f and adds 1 to it.

g4 takes the output of f and finds the absolute value of it.

g5 takes the output of f and applies the sine function to it.

(b) The expressions for g as a function of f can be written as:

g1(f) = 2 ˣ f

g2(f) = f²

g3(f) = f + 1

g4(f) = |f|

g5(f) = sin(f)

Each of these functions g is defined in terms of the input function f, and the transformations from f to g are clear from the expressions for g.

These transformations can be applied to any input function f to produce a corresponding output function g.

Learn more about transformations

brainly.com/question/13801312

#SPJ11

An optional vacuum mount for the Yaesu FTM-400DR control head is the Yaesu MMB-98.

To learn more about YAESU System, refer to :

https://brainly.com/question/15727329

#SPJ4

The key factor that has contributed to the growth and popularity of big data is the implosion in data growth.

The growth and popularity of big data can be largely attributed to the implosion in data growth. The continuous advancement of technology, particularly mobile and wireless technology, has led to an exponential increase in the amount of data being generated and collected.

Mobile devices, such as smartphones and tablets, have become ubiquitous in today's society, enabling people to create and consume vast amounts of data on a daily basis. These devices are equipped with various sensors, cameras, and applications that generate data related to users' activities, preferences, locations, and more. Additionally, the widespread adoption of wireless connectivity has made it easier to capture and transmit data in real-time.

The implosion in data growth has revolutionized the way organizations operate and make decisions. The availability of large volumes of data has opened up new possibilities for data-driven insights, predictive analytics, and business intelligence. Companies can now analyze vast datasets to uncover patterns, trends, and correlations that were previously hidden. This has led to improvements in customer experiences, targeted marketing strategies, operational efficiencies, and innovation in various industries.

In summary, the implosion in data growth, driven by mobile and wireless technology, has played a significant role in the growth and popularity of big data, enabling organizations to harness the power of data for decision-making and competitive advantage.

Learn more about  technology here: https://brainly.com/question/11447838

#SPJ11

In contrast to turbulent flow, in which the fluid experiences random fluctuations and mixing, laminar flow, also known as streamline flow, is a type of fluid (gas or liquid) movement in which the fluid travels smoothly or along regular patterns.

Thus, The velocity, pressure, and other flow characteristics at every location in the fluid are constant in laminar flow.

One way to conceptualize laminar flow over a horizontal surface is as tiny layers, or laminae, that are all parallel to one another.

All other layers slide over one another, but the fluid in contact with the horizontal surface remains immobile. To use a loose comparison, imagine how a deck of fresh cards might "flow" laminarly

Thus, In contrast to turbulent flow, in which the fluid experiences random fluctuations and mixing, laminar flow, also known as streamline flow, is a type of fluid (gas or liquid) movement in which the fluid travels smoothly or along regular patterns.

Learn more about Laminar flow, refer to the link:

https://brainly.com/question/23008935

#SPJ4

Answer: the shear strength at a depth of 12 ft is 1034.9015 lb/ft²

Explanation:

Given that;

Weight of soil r = 118 lb/ft³

stress parameter C = 250 lb/ft²

φ total = 29°

depth Z = 12 ft

The shear strength on a horizontal plane at a depth of 12ft

ζ = C + δtanφ

where δ = normal stress

normal stress δ = r × z = 118 × 12 = 1416

so

ζ = C + δtanφ

ζ = 250 + 1416(tan29°)

ζ = 250 + 1416(tan29°)

ζ = 250 + 784.9016

ζ = 1034.9015 lb/ft²

Therefore the shear strength at a depth of 12 ft is 1034.9015 lb/ft²

When a neuron sends a signal, they create electrical events called actions potentials and chemical neurotransmitters.

Basically, a neuron is a fundamental units of the brain and nervous system. They are nerve cells responsible for: receiving sensory input from the external world, sending motor commands to the muscles, and for transforming and relaying electrical signals.

Being that neurons also communicates, they do so using electricals and chemicals means. So one neuron can communicate to the other via electrical events which are action potentials and chemical neurotransmitters.

An action potential causes one neuron to release chemical neurotransmitter which will help or hinder the other neuron from firing its own action potential.

In summary, neurons are essentially electrical devices having action potentials and chemical neurotransmitters as the fundamental units of sending signals or communicating with other neurons.

Learn more about neuron's signals here:

https://brainly.com/question/10777049

#SPJ4

Answer:

C. Heavy-gauge sheet metal.

Explanation:

Exhaust manifolds are typically made from cast iron, aluminum, or stainless steel, which are strong and durable materials that can withstand the high temperatures and pressures found in vehicle exhaust systems.

Heavy-gauge sheet metal is a type of metal, but it is not typically used for this application because it may not have the necessary strength and durability.

Answer:

The major financial flop that led to the end of the Sega Dreamcast and ultimately caused Sega to stop making game consoles altogether is:

3: A game called Shenmue, that cost more than $70 million to make, meant that everyone who owned a Dreamcast needed to buy two copies of the game just for Sega to make back the money they had spent to develop it-which didn't happen.

Explanation:

Shenmue, released on December 29, 1999, was created for Dreamcast by Suzuki.  It was widely described as the most expensive video game ever produced.  It had an estimated production and marketing cost of between US$47 and $70 million, according to the latest available data.

Answer:

Automation generally means “a process performed without human assistance”, while autonomy implies “satisfactory performance under significant uncertainties in the environment and the ability to compensate for system failures without external intervention [emphasis mine].”

Explanation:

The tatal resistance of the series-parallel circuit with two resistor connected in parallel which combination is connected in series to a single resistor is 9 ohms.

This can be defined as the opposition to current flow in a circuit.

To calculate the total resistance, first we need to find the total resistance of the parallel resistor.

For parallel,

Where:

R' = Total resistance of the parallel resistor.

From the question,

Given:

Substitute these values into equation 1

Finally, we combine the effective parallel resistance in series to the single resistance to the the total resistance of the circuit.

Where:

From the question,

Substitute these values into equation 2

Hence, the total resistance of the circuit is 9 ohms.

Learn more about resistance here: https://brainly.com/question/28135236

#SPJ1

Answer:

Wood is heavy

Explanation:

Before joining a fitting and pipe using socket fusion, it is important to ensure that both the fitting and pipe are clean and free from any debris or contaminants. Additionally, the correct size fitting and pipe must be used to ensure a proper fit.

Socket fusion is a method of joining plastic pipes and fittings together by heating the material and then pressing the heated ends together to form a strong bond. Before the socket fusion process begins, it is important to prepare both the fitting and pipe by ensuring they are clean and free from any debris or contaminants.

This can be achieved by using a specialized cleaning tool or wiping the surfaces with a clean cloth. Additionally, it is crucial to use the correct size fitting and pipe to ensure a proper fit and prevent any leaks or issues in the future. Proper preparation of the materials is crucial to ensuring a successful socket fusion joint.

For more questions like Socket click the link below:

https://brainly.com/question/29658250

#SPJ11

The "getNumber" module accepts an Integer argument as a reference parameter variable. It displays a prompt asking the user to enter a number. The user's input is then stored in the reference parameter variable.

Here's the pseudocode for the "getNumber" module that prompts the user to enter a number and stores it in a reference parameter variable:

module getNumber(numberRef):

   display "Enter a number: "

   input number

   numberRef = number

The "getNumber" module uses a reference parameter variable to accept an Integer argument. By passing the variable by reference, any changes made to the variable inside the module will affect the original variable outside the module. The module begins by displaying the prompt "Enter a number: ". This prompt informs the user to input a number. The module then uses the "input" statement to read the user's input from the keyboard and assigns it to the local variable "number". Finally, the value of "number" is assigned to the reference parameter variable "numberRef". Since "numberRef" is a reference parameter, this assignment updates the value of the original variable passed as an argument to the module. By using this module, you can call it in your program and pass an Integer variable as an argument to store the user's input in that variable.

Learn more about parameter variable here:

https://brainly.com/question/17587384

#SPJ11

Answer:

SECTION LEARNING OBJECTIVES

By the end of this section, you will be able to do the following:

Distinguish between static friction and kinetic friction

Solve problems involving inclined planes

Section Key Terms

kinetic friction static friction

Static Friction and Kinetic Friction

Recall from the previous chapter that friction is a force that opposes motion, and is around us all the time. Friction allows us to move, which you have discovered if you have ever tried to walk on ice.

There are different types of friction—kinetic and static. Kinetic friction acts on an object in motion, while static friction acts on an object or system at rest. The maximum static friction is usually greater than the kinetic friction between the objects.

Imagine, for example, trying to slide a heavy crate across a concrete floor. You may push harder and harder on the crate and not move it at all. This means that the static friction responds to what you do—it increases to be equal to and in the opposite direction of your push. But if you finally push hard enough, the crate seems to slip suddenly and starts to move. Once in motion, it is easier to keep it in motion than it was to get it started because the kinetic friction force is less than the static friction force. If you were to add mass to the crate, (for example, by placing a box on top of it) you would need to push even harder to get it started and also to keep it moving. If, on the other hand, you oiled the concrete you would find it easier to get the crate started and keep it going.

Figure 5.33 shows how friction occurs at the interface between two objects. Magnifying these surfaces shows that they are rough on the microscopic level. So when you push to get an object moving (in this case, a crate), you must raise the object until it can skip along with just the tips of the surface hitting, break off the points, or do both. The harder the surfaces are pushed together (such as if another box is placed on the crate), the more force is needed to move them.