A body moves with a velocity of 30.0 m/s.
This speed is increased to 40 m/s in 4.0s.
Calculate
a) the average acceleration of the body.
b) the distance covered by the body.​

When a man pushes a box across a floor, as he increases the force he applies horizontally to the box, then the kinetic friction remains the same.

To find the answer, we need to know about friction.

Thus, we can conclude that, kinetic friction remains the same when we increase the applied force.

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As a guy pushes a box across a floor, the kinetic friction stays constant no matter how much force is applied on the box horizontally.

We must understand friction if we are to find the solution.

We can therefore draw the conclusion that kinetic friction does not change as the applied force is increased.

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Answer:

when an object kept at some height and having some mass then ,when it falls down then shifting of energy takes place

The time taken for the coffee to cool from 93°C to 73°C is approximately 36.1 minutes.

The cooling law is given by:

$$\frac{dQ}{dt}=-k(T-T_0)$$

where Q is the heat in the object, t is the time taken, T is the temperature of the object at time t, T0 is the temperature of the environment and k is a constant known as the cooling constant.

We need to find the time it takes for the coffee to reach a drinking temperature of 73°C given that its initial temperature is 93°C.

Therefore, we need to find the time it takes for the coffee to cool down from 93°C to 73°C when placed in a room temperature of 18°C.

Let’s assume that the heat energy that is lost by the coffee is equal to the heat energy gained by the environment. We can express this as:

dQ = - dQ where dQ is the heat energy gained by the environment.

We can substitute dQ with C(T-T0) where C is the specific heat capacity of the object.

We can rearrange the equation as follows:

$$-\frac{dQ}{dt}=k(T-T_0)$$

$$-\frac{d}{dt}C(T-T_0)=k(T-T_0)$$

$$\frac{d}{dt}T=-k(T-T_0)$$

The differential equation above can be solved using separation of variables as follows:

$$\frac{d}{dt}\ln(T-T_0)=-k$$

$$\ln(T-T_0)=-kt+c_1$$

$$T-T_0=e^{-kt+c_1}$$

$$T=T_0+Ce^{-kt}$$

where C = e^(c1).

We can now use the values given to find the specific value of C which is the temperature difference when t=0, that is, the temperature difference between the initial temperature of the coffee and the room temperature.

$$T=T_0+Ce^{-kt}$$

$$73=18+C\cdot e^{-0.09t}$$

$$55=C\cdot e^{-0.09t}$$

$$C=55e^{0.09t}$$

$$T=18+55e^{0.09t}$$

We can now solve for the value of t when T=93 as follows:

$$93=18+55e^{0.09t}$$

$$e^{0.09t}=\frac{93-18}{55}$$

$$e^{0.09t}=1.3636$$

$$t=\frac{\ln(1.3636)}{0.09}$$

Using a calculator, we can find that the time taken for the coffee to cool from 93°C to 73°C is approximately 36.1 minutes.

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The turns ratio of the transformer is 1:7.5. Therefore, if the primary coil has 200 loops, the secondary coil has 1500 loops.

The turns ratio of a transformer is defined as the ratio of the number of turns in the secondary coil to the number of turns in the primary coil. In this case, the turns ratio is 1500/120 = 12.5. Since the turns ratio is the ratio of the number of turns in the secondary coil to the number of turns in the primary coil, we can write:

Number of turns in secondary coil / Number of turns in primary coil = Turns ratio

Substituting the values given in the problem, we get:

Number of turns in secondary coil / 200 = 12.5

Solving for the number of turns in the secondary coil, we get:

Number of turns in secondary coil = 200 x 12.5 = 2500

Therefore, the number of turns in the secondary coil is 2500.

The amount by which a transformer steps up or steps down the voltage depends on its turn ratio. In this instance, a factor of 1500/120 = 12.5 results in an increase in voltage. The output voltage is 12.5 times more than the input voltage, according to this. The physical structure of the transformer, specifically the number of turns in the main and secondary coils, determines the turn ratio.

It's vital to remember that the transformer uses the electromagnetic induction principle to function. A magnetic field is created when an AC voltage is delivered to the primary coil; this magnetic field causes a voltage to be induced in the secondary coil. The secondary coil's voltage is inversely proportional to the coil's number of turns. The transformer can therefore step up or step down the voltage by adjusting the number of turns in the primary and secondary coils.

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Answer:

The source of energy that is used to power the movement of contraction in working muscles is adenosine triphosphate (ATP) – the body's biochemical way to store and transport energy. However, ATP is not stored to a great extent in cells. So once muscle contraction starts, the making of more ATP must start quickly.

Explanation: Brainliest?

Answer:

sustainability over time.

Explanation:

The largest Brazilian rainforest is the Amazon rainforest, which is the largest rainforest in the world and occupies 42% of the Brazilian territory. The forest is composed of a rich environmental diversity, constituted by many species of fauna and flora and diverse river resources.

However, there is a growing transformation in the Amazon rainforest caused by organizational exploitation that uses its resources to transform the forest area into agricultural land and pastures for livestock. This problem will cause a reduction in sustainability over time, which will cause serious negative effects on the environment, such as a reduction in biodiversity and an increase in the emission of gases responsible for the greenhouse effect on the planet.

Answer:

Bb

Explanation:

The resistance of the electric heating element can be determined using Ohm's law, which states that resistance (R) is equal to voltage (V) divided by current (I). In this case, the voltage across the element is given as 232 volts and the current flowing through it is 19 amperes. The correct option is 12 ohms.

Applying Ohm's law, we calculate the resistance as:

R = V / I

R = 232 volts / 19 amperes

R ≈ 12 ohms

Therefore, the resistance of the element is approximately 12 ohms. This means that for every ampere of current flowing through the element, there is a voltage drop of 12 volts. The resistance value of 12 ohms indicates that the element has a moderate level of electrical resistance, which allows it to generate heat efficiently when current flows through it. Thus, the correct option is 12 ohms.

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The distance travelled by the ball from its starting position is 120 m.

option E is the correct answer.

The time of motion of the ball is calculated by applying the following kinematic equation as shown below.

v = u - gt

where;

At maximum height, final vertical velocity = 0

0 = u - gt

gt = u

t = u / g

t = ( 20 ) / ( 10 )

t = 2 s

The time taken for the ball to go up and come down = 2 x 2 s = 4 s

The horizontal distance travelled by the ball = 30 m/s x 4 s = 120 m

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Streamflow is the flow of water in streams, rivers, and other channels, and is a key component of the water cycle. It's influenced by a variety of factors, including the shape and depth of the riverbed, the gradient of the stream, the size and shape of the channel, and the amount of water flowing through it. The given statement is false.It is affected by many factors.

All of these factors influence the velocity of the streamflow. Riverbed and streamflow relationshipThe velocity of streamflow is primarily influenced by the gradient or slope of the riverbed. A shallow slope will not yield high velocity streamflow, but instead will create a slow-moving, meandering stream with a high potential for sedimentation and erosion. In contrast, a steep gradient will create a fast-moving stream with a higher velocity and more turbulent water. As a result, a steeper slope will produce higher velocity streamflow than a shallower slope, which will produce slower-moving streamflow. Therefore, a riverbed with a shallow slope will not yield high velocity streamflow. The statement is false.

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Answer: Hello! An objects speed is constant and has the units meters per second (m/s); thus, it does not change overtime. Acceleration is a rate of change where the speed does either increase or decrease overtime from its inital value; its units are meters per second second (m/s/s). I hope that helps!

Answer:

3 m/s²

Explanation:

Take the difference between the initial speed(0) and final speed (30) and divide it by time (10).

final speed - initial speed

——_----------------------------

time.

Answer:

C

Explanation:towards Erin

The rope will move towards Erin because, the force between them is unbalanced and the more force is exerted by Erin. Hence, the displacement will occur on the greater force side.

Force is an external agent acting on a body to change its motion or to deform it. The net force acting on the body depends on the direction and magnitude of all  the force acting on it.

If two equal forces acts on the body from the same side they add up together and the net force is their sum. If the forces are acting from the opposite sides, they will cancel each other and is said to be balanced.

Here, two forces from the side is un balanced by a force from the opposite side. Hence, the greater force from Erin will make the rope displaced towards her side. Thus, option C is correct.

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The  displacement skydiver stepping from a helicopter hovering thousands of meter above the ground is 60.025 m downward.

Displacement is the distance of a body in a specified direction.

To calculate the skydiver's displacement, we use the formula below.

Formula:

Where:

From the question,

Given:

Substitute these values into equation 1

Hence, the skydiver's displacement is 60.025 m downward.

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If the total mechanical energy of a swinging pendulum is 126 J, and its mass is 9.0 kg, the maximum height reached by the swinging pendulum is 1.4 m.

Mechanical Energy can be defined as the sum of potential energy and kinetic energy at any point.

The expression for mechanical energy is

M.E = Ek+Ep

Where,

Ek = Kinetic energy, Ep = Potential energy.

Note: At maximum height, the Kinetic energy of a swinging pendulum is zero. i.e., Ek = 0 J

Therefore,

M.E = Ep = mgh

Where, m = mass of the pendulum, h = maximum height reached , g = acceleration due to gravity.

Here, h can be expressed by the equation.

h = M.E/mg

From the question,

Given: m = 9 kg, M.E = 126 J, g = 10 m/s²

Substitute these values in the above equation,

h = 126 / (9×10)

h = 126 / 90

h = 1.4 m

Hence, the maximum height reached by the swinging pendulum is 1.4m.

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Answer:

Acceleration

Explanation:

The advertisement is describing the acceleration of the car.

Acceleration is the rate of change of velocity per unit of time. It can be expressed mathematically as;

 Acceleration  = \(\frac{v - u}{t}\)  

 v is the final velocity

 u is the initial velocity

 t is the time taken

 Any quantity that specifies the rate of change of velocity of a body within a given time frame is describing its acceleration.

Write an expression for the x-component of acceleration of the given velocity field as a function of x, y, z, and/or t.

v={4yti-2xtj}m-s

We frequently wish to know an object's acceleration vector at any point along its trajectory in addition to its displacement and velocity vectors. This acceleration vector, which represents the instantaneous acceleration, may be found by taking the velocity function's derivative with respect to time, as we saw in the previous chapter. The fact that these are now vector quantities is the only variation in two or three dimensions. The same approach that was demonstrated in the previous chapter for one-dimensional motion can be used to tackle multidimensional motion with constant acceleration. As we previously demonstrated, motion in three dimensions is comparable to motion in three one-dimensional space along axes that are all perpendicular to one another.

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The current density in the hollow copper wire is approximately 2.09 × 10⁶ A/m².

To calculate the current density in the hollow copper wire, we'll first need to determine the cross-sectional area of the wire. Given the inner diameter of 1.2 mm and outer diameter of 2.5 mm, we can find the area as follows:
1. Convert diameters to radii: inner radius (r1) = 0.6 mm, outer radius (r2) = 1.25 mm
2. Convert radii to meters: r1 = 0.0006 m, r2 = 0.00125 m
3. Calculate the cross-sectional area: Area = π(r2² - r1²)
Area = π((0.00125)² - (0.0006)²) = 3.82116 × 10⁻⁶ m²
Now we can find the current density (J) using the formula J = I/Area, where I is the current (8.0 A) and Area is the cross-sectional area calculated above.
J = 8.0 A / 3.82116 × 10⁻⁶ m² ≈ 2.09 × 10⁶ A/m²

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Answer:

^ correct

Explanation:

Option A on edge 2020

Answer:

A wind turbine transforms the mechanical energy of wind into electrical energy. A turbine takes the kinetic energy of a moving fluid, air in this case, and converts it to a rotary motion. As wind moves past the blades of a wind turbine, it moves or rotates the blades. These blades turn a generator

The electrical current is conveyed from the revolving portion of the crane to the lower crane structure through the collector ring system.

The movement of electrical charges through space or a conductor is called electric current.

It is a stream of particles having definite charges that flow between two endpoints of a conductor.

Daily life examples include watching TV, charging a cell phone, turning a light on, cooking a stove, and starting a car.

In Si units, electric current is measured in ampere i.e. A. It means the flow of one-coulomb charge through a point in one second.

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We first draw a force diagram that shows the forces acting on the child-seat system and apply Newton's second law to solve the problem. The child's path is an arc of a circle, since the top ends of the chains are fixed. Then at the lowest point the child's motion is changing in direction: He moves with centripetal acceleration even as his speed is not changing and his tangentialacceleration is zero.

∑F=Fnet=2T−mg=ma= mv²/r

With:

Fnet =2T−mg=2(300N)−(40.0kg)(9.80m/s² )=208N

solving for v gives,

\(v = \sqrt{ \frac{f \:net.r}{m} } = \sqrt{ \frac{208.3}{40} } = 3.95 \frac{m}{s} \)

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The properties of group 18 elements, also referred to as noble gases or group 8 elements.

Eight valence electrons make them up.

They have enough electrons in their octet, therefore they don't need any more (stable).

are steady

Noble gases are those that are not reactive.

In order to gain or lose valence electrons to the element they interact with, elements create ions. They acquire a whole octet as a result. You might be wondering what a whole octet is. When an element contains all 8 valence electrons and is stable, it is said to have an octet, rendering it nonreactive.

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Answer:

1100 m

Explanation:

To solve this problem, we must note that the airplane does not make a full circle. Instead, it turns from flying east to flying south. Check the attachment for a visual of this path.

We can use this equation:

We are given the velocity and time of the airplane; therefore, we can solve for d in the equation.

The distance that the airplane travels is 1725 m.

Now, using our knowledge we know that the circumference of a circle is 2πr, and this is the distance traveled for an object in a circular motion.

However, in this problem, the airplane only travels for a fourth of a circular path, so we can use \(\displaystyle \frac{2\pi r}{4}\). This gives us 1/4 the circumference of a circle.

This is equal to the distance (1725 m) the airplane travels:

Multiply 4 to both sides of the equation.

Divide both sides by 2pi.

The radius of the curve that the plane follows in making the turn is about 1100 m.

The force experienced will be 8E-15 N.

A thin circular sheet of glass with a diameter of 7 meters has been rubbed with a cloth on one of its surfaces, resulting in a uniform charge.

A chloride ion, consisting of a chlorine atom which has gained an extra electron, passes near the glass sheet. When the chloride ion is 0.8 mm away from the center of the sheet, it experiences an electric force of 8E-15 N, directed towards the glass sheet. Using the value 8.85e-12 C2/(N·m2), this force can be calculated as follows:

F = 8.85e-12 x (Q1 x Q2) / d2

Where Q1 and Q2 are the charge of the chloride ion and the glass sheet, respectively, and d is the distance between them (0.8 mm).

Therefore, the force experienced by the chloride ion is 8E-15 N, as expected.

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The maximum temperature allowed for silicon is 383 degree Celsius.

The intrinsic carrier concentration, ni, in silicon can be determined using the following equation:

ni^2 = Nc * Nv * exp(-Eg/kT)

Rearranging the equation as follows:

T = Eg / (2 * k * ln(ni^2 / Nc / Nv))

The values of Nc and Nv can be calculated using the following equations:

Nc = 2 * [(2πmkT/h^2)^(3/2)]

Nv = 2 * [(2πmkT/h^2)^(3/2)] * exp(-Eg/kT)

Using typical values for the effective masses of electrons and holes in silicon (m_e = 0.26 m_0, m_h = 0.36 m_0, where m_0 is the rest mass of an electron), we can calculate Nc and Nv as:

Nc = 2.81 x 10^19 cm^-3

Nv = 1.83 x 10^19 cm^-3

Substituting these values into the equation for T, we get:

T = (1.12 eV) / [2 * (1.38 x 10^-23 J/K) * ln((1 x 10^12 cm^-3)^2 / (2.81 x 10^19 cm^-3) * (1.83 x 10^19 cm^-3))]

T = 656 K or 383 °C

Therefore, the maximum temperature allowed for silicon with an intrinsic carrier concentration no greater than 1x10^12 cm^-3 is approximately 656 Kelvin or 383 degrees Celsius.

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Answer:16.7watt

Explanation:

Answer:

Presión = 11111,11 N/m

Explanation:

Dados los siguientes datos;

Diámetro = 1,5 cm a metros = 1,5 / 100 = 0,015 m

Fuerza = 2N

Para encontrar la presión;

En primer lugar, determinaríamos el área del círculo usando la fórmula;

Área del círculo = πr²

Radio = diámetro/2 = 0.015/2 = 0.0075 m

Área de la jeringa = 3.142 * 0.0075²

Área de la jeringa = 3.142 * 0.00005625

Área de la jeringa = 0.00018 metros

Ahora, podemos encontrar la presión usando la fórmula;

Presión = fuerza/área

Presión = 2/0.00018

Presión = 11111,11 N/m