Hi, Can anyone help me? I don't understand.

A car horn has a frequency of 448 Hz when the car is stationary. If the car approaches a stationary recorder at a speed of 19.0 m/s, what frequency does the device record if the temperature is 20°C? What frequency does the device record after the car passes by?

**SHOW CALCULATIONS, PLEASE!

The normal force felt by the box has magnitude

F[normal] = (1 kg) g = 9.8 N

so that the maximum magnitude of static friction is

F[s. friction] = 0.8 F[normal] = 7.84 N

In order to get the box to move, (C) a minimum force of 7.84 N is required.

The angular velocity of link BD is 2.89 rad/s and the angular acceleration is 0 rad/s².

The expression for angular acceleration can be calculated by applying the vector method.

Here, the vector method of angular velocity will be applied to get the expression for angular velocity ω2 and angular acceleration α2 as follows:

Step 1:Velocity of the collar relative to B and velocity of point A of the link AB and collar can be written as VB = VA + AB X ω1

Here, AB is perpendicular to the plane of rotation, and the velocity of A relative to the collar is ω1 * AB.

Therefore, AB X ω1 = 0 as AB is parallel to AB. Thus, VB = VA.

Then, the velocity of point B can be given as:

VB = BD X ω2Hence, BD X ω2 = VA, we get: ω2 = VA / BD

Step 2: Acceleration of point A relative to collar: AB X α1 = 0 (AB parallel to the plane of rotation)

AA = AB X ω1 X ω1=0

Acceleration of point A relative to C: AC X α1 = AC X 10α2=0

Since, AC=AB=1m

α2=0

Acceleration of collar C relative to point B: BD X α2=VA

Here, α2 = 0, and VB = VA = 5m/s.

Hence:BD * 0 = 5m/sω2 = VA / BD= 5 / (1.732 x 1)=2.89 rad/s

Thus, the angular velocity of link BD is 2.89 rad/s and the angular acceleration is 0 rad/s².

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Answer:

Wandering Slowly with no pattern

Explanation:

I apologize to those who got it wrong from the first person.

The Earth's magnetic pole is wandering slowly with no pattern. Then the correct option is D.

Magnetic poles are the points near the extremities of the axis of rotation of the Earth or another celestial body where a magnetic needle dips vertically.

At either end of a magnet, the magnetic pole is where the applied magnetic field is strongest. An imaginary basic particle known as a magnetical monopole may be referred to as a magnet's pole. A unique type of magnet is the magnetism poles of celestial bodies.

The north magnetism pole of the earth Today is located where the north arrow is on a path leading downhill.

The magnetic pole is located far away from the geographic pole.

Earth's magnetic pole is defined as wandering slowly with no pattern.

Thus, the correct option is D.

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This is due to the fact that occluded fronts combine two cold air masses, which causes one of the cold air masses to go downward.

When a warm air mass is sandwiched between two cold air masses, an occluded front occurs. In an occlusion, the warm front passes over the cold front, which dives beneath it.

In a front is obscured, the warm front is fully supplanted by the cold front, in which the warm air masses have completely disappeared. Furthermore, there are frequent shifts in the various weather producing circumstances because of the cold front's relatively low temperature.

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Average number of team members who reached their goal per day = 4.2

Number of team members that reached their goals on Monday = 5

Number of team members that reached their goals on Tuesday = 4

Number of team members that reached their goals on Wednesday = 2

Number of team members that reached their goals on Thursday = 7

Number of team members that reached their goals on Friday = 3

Total number of team members that reached their goals = 5 + 4 + 2 + 7 + 3

Total number of team members that reached their goals = 21

Average number of team members who reached their goal per day = 21/5

Average number of team members who reached their goal per day = 4.2

Answer:

S = θ R      where S is the arc length and θ the arc length in radians

S = 2.5 ft * 4 π^3 rad = 2.5 * 124 = 310 ft       (1 radian = 2.5 ft)

Assuming 4π3 means 4π^3

The Reagan travel over an angle of 4π/3radians is 10.47 or 10 feet if the Reagan rides on a playground roundabout with a radius of 2. 5 feet.

It is defined as the combination of points that and every point has an equal distance from a fixed point ( called the center of a circle).

We have Reagan rides on a playground roundabout with a radius of 2.5 feet.

We know the relation between arc length and radius of the circle:

S = R∅

Here R = 2.5 feet, and central angle ∅ = 4π/3

\(\rm S = 2.5\times \frac{4\pi}{3}\)

S = 10.47 feet ≈ 10 feet

Thus, the Reagan travel over an angle of 4π/3radians is 10.47 or 10 feet if the Reagan rides on a playground roundabout with a radius of 2. 5 feet.

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The modifications to the car design that would have the greatest effect on increasing the kinetic energy of the car is to increase the mass of the car slightly (option B).

Kinetic energy is the energy possessed by an object because of its motion. The kinetic energy equal (nonrelativistically) to one half the mass of the body times the square of its speed.

According to this question, an engineer is designing a small toy car that will be launched from rest. The engineer wants to maximize the kinetic energy of the car when it is launched by a compressed spring.

However, he can only make one adjustment to the initial conditions of the car. Considering the fact that the mass of an object is directly proportional to the kinetic energy.

This suggests that the modifications to the car design that would have the greatest effect on increasing the kinetic energy of the car is to increase the mass of the car slightly.

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(1) The voltage drop in the second resistor is 10 V.

(2) The voltage drop across each resistor will all double to match change in resistance.

The given parameters:

The total voltage in a series circuit is given as;

\(V_T = IR_1 + IR_2\\\\V_T = V_1 + V_2\)

The voltage drop in the second resistor is calculated as follows;

\(V_2 = V_T - V_1\\\\V_2 = 15 - 5\\\\V_2 = 10 \ V\)

(2)

The resistance of the circuit:

\(R = \frac{V}{I} = \frac{10}{2} = 5 \ ohms\)

When the total resistance is doubled;

In series circuit, the current in each resistor is constant, the voltage drop is calculated as;

\(V = IR\\\\V = 2 (5+5)\\\\V = 20 \ V\)

Thus, we can conclude that the voltage drop across each resistor will all double to match change in resistance.

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Answer:

-Relative refractive index– It is the ratio of speed of light in one medium to the speed of light in another medium

-Absolute refractive index– It is the ratio of light in vacuum to the speed of light in another medium.

Explanation:

a. To determine the final dilution, we need to multiply the individual dilution factors. In this case, the dilution factors are \(1/2\), \(1/4\), and \(1/8\). So the final dilution factor is \( (1/2) \times (1/4) \times (1/8) = 1/64 \).

The final dilution refers to the overall dilution achieved after a series of successive dilutions. It is the cumulative effect of all the individual dilution factors applied in the dilution process.

b. The reported concentration is \(4 \mathrm{mg/dL}\). Since the final dilution factor is \(1/64\), we need to divide the reported concentration by the dilution factor to obtain the actual concentration of the original sample.

Actual concentration = Reported concentration / Dilution factor

Actual concentration = \(4 \mathrm{mg/dL} \) / \(1/64\) = \(256 \mathrm{mg/dL}\).

Therefore, the final dilution is \(1/64\) and the reported concentration of the original sample is \(256 \mathrm{mg/dL}\).

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The combination of high elevation and high latitude generally results in the coldest temperatures.

option D.

Elevation refers to the height of a location above sea level, and latitude refers to the distance of a location from the equator. In general, higher elevations are colder due to the decrease in atmospheric pressure, which leads to lower temperatures. Similarly, higher latitudes are colder because they receive less direct sunlight and are farther away from the equator.

When both high elevation and high latitude are combined, the temperature tends to be the coldest. This is because high elevation areas are often located at higher latitudes, such as in mountainous regions near the poles, where the combination of lower temperatures due to elevation and lower temperatures due to latitude results in even colder temperatures.

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Number of electrodes should be attached to the left forearm to record a 3 lead ECG is option (c) 2

A 3 lead ECG uses three electrodes to measure the electrical activity of the heart from different angles. To record a 3 lead ECG, two electrodes are placed on the left forearm and one electrode is placed on the left leg. The two electrodes on the left forearm are placed in a bipolar configuration, with one electrode placed just above the wrist and the other placed just below the elbow.

The electrode on the left leg is placed on the ankle, and it serves as a reference point for the other two electrodes on the left forearm. By measuring the electrical activity of the heart from three different angles, a 3 lead ECG can provide information about the functioning of the heart and detect abnormalities in its electrical activity.

Therefore, the correct option is (c) 2

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Explanation:

I=MV

=225×(15- 21)

=225×-5

Answer:

B. 1350 kg•m/s east

Explanation:

........

Answer:

Explanation:

Inertia is one of the major properties of all objects which makes an object at rest to be reluctant to move and an object in motion to be reluctant to stop.

Therefore during the stirring of the coffee, the molecules of the mixture were in a continuous circular motion. But after the stirring has ceased, the molecules were reluctant to stop. Thus the motion continues for sometime until some available damping forces acts.

Thus the observation by Radha with respect to the motion of the coffee.

Answer:

You must exert a force of 4.5 N on a book to slide it across a table.

Explanation:

The distance of the speaker B would be 1 meters.

Given that,

Frequency of the waves emitted, f = 172 Hz

You are 8.00 m from the speaker.

The speed of sound in air to be 344 m/s.

The wavelength of the wave is given in terms of frequency and the speed of sound. It is given by :

v = fλ

λ = f / v

λ = 344 / 172 Hz

λ = 2 m

Since, the distance from the Speaker A is 8 m which is the integral multiple of the wavelength. Let the closest distance of the speaker B would be given by :

d = λ / 2

d = 2 / 2

d = 1 m

Therefore, the distance of the speaker B would be 1 meters.

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Answer:

The time between the emission of the wave and it's reception was 0.4 seconds.

Explanation:

The sound wave emitted by the sonar traveled from the boat to the fishes and came back, therefore the distance of it's total route is twice the distance from the boat to the fishes. We can apply the average speed formula in order to solve this problem, this is done below:

\(\text{speed} = \frac{\text{distance}}{\text{time}}\)

We were given the distance traveled by the wave and it's speed, therefore we can solve for the time:

\(\text{time} = \frac{\text{distance}}{\text{speed}}\\\\\text{time} = \frac{(2*300)}{1500}\\\\\text{time} = \frac{600}{1500} = 0.4 \text{ s}\)

The time between the emission of the wave and it's reception was 0.4 seconds.

Answer:

Yes

Explanation:

Displacement is the distance from the starting point to the end point. If you live and die at the same place, you will have 0m as your displacement.

Answer:

a basis or standard for evaluation, assessment, or comparison; a criterion.

Explanation:

Definition of reference point. : something that is used to judge or understand something else The professor used the study as a reference point for evaluating and discussing other theories.

Answer:

something that is used to judge or understand something else

Explanation:

The professor used the study as a reference point for evaluating and discussing other theories.

Answer:

1-Average speed

2-constant

Explanation:

Question 1 : You have the distance and time , need to find average speed

Question 2 : traveling at the same speed that means it's constant

Answer:

second law is f=ma (force=massxacceleration)

Explanation:

D. Water in the pot is heated by convection. Water molecules at the bottom of the pot warm up and rise while cooler water molecules sink to the bottom of the pot, creating convection currents.

Convection currents are flowing fluid that is moving because there is a temperature or density difference within the material.

Convection heat transfer takes place only in liquids and gases.

During heat transfer by convection, the heated air will rise to the top due o its lower density while the cooler air will sink to the bottom due to its higher density.

Thus, for the model of a pot of water being heated on a stove that shows thermal energy transfer, the heat transfer occurs when the water in the pot is heated by convection. Water molecules at the bottom of the pot warm up and rise while cooler water molecules sink to the bottom of the pot, creating convection currents.

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Heat is transferred to the water. The water molecules which are in the pot become more active, and the temperature of the water rises.

What is the Kinetic energy?

Kinetic energy is the energy of the objects which is present due to the motion of the object. Kinetic energy is proportional to the mass and velocity of the object. The SI unit of Kinetic energy is Joule (J).

The kinetic energy is possessed due to the motion of the particles. The kinetic energy is directly proportional to the temperature of objects. The kinetic energy of the particles increases with the rise in temperature of object or solution.

In the given situation, the pot of water is placed on the stove. Then, the heat is transferred to the water in pot. The water molecules will move faster with the rise in temperature of the water. The water molecules will have greater amount of kinetic energy due to increase in temperature.

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Answer: 50°

Explanation:

Given the following :

Initial Velocity of bullet (U) = 87m/s

Time of travel (t) = 13.6s

Horizontal Distance traveled (S) = 760m

Therefore, the horizontal angle of projection of the bullet :

Using the second equation of motion:

S = ut + 0.5at^2

Where a = g = acceleration due to gravity, S = distance traveled, t= time taken and U = Initial Velocity.

The Angle of projection along the horizontal is represented as cosΘ

Acceleration due to gravity after the bullet has hit the ground = 0

Therefore, rewritten the equation :

S = ucosΘ * t + 0.5at^2

760 = 87 * Cosθ * 13.6 + 0.5(0)(13.6)^2

760 = 1183.2 * Cosθ + 0

Cosθ = 760 / 1183.2

Cosθ = 0.6423

Θ = cos^-1(0.6423)

Θ = 50.036460

Θ = 50°

Answer:

Conduction and convection requires Modes of transfer of heat ! Radiation doesn't require any medium !!

In terms of heat transfer, radiation is the emission of thermal energy in the form of infrared waves. ... Since heat is carried by electromagnetic waves, it does not need a physical medium to transfer it. Instead it radiates through space - this is how the Earth is heated by the Sun despite space being a vacuum

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Answer:

239.2 N

Explanation:

Given that a vertical rope is attached to an object that has a mass of 40.0 kg and is at rest.The tension in the rope needed to give the object an upward speed of 3.50 m/s

in 0.700 s is

The tension in the rope and the weight of the mass will be acting in an opposite direction.

T - mg = ma ....... (1)

Where acceleration a = Velocity/ time

a = 3.5 / 0.7

a = 5 m/s^2

Substitutes acceleration a into the equation 1 above.

T - 40 × 9.8 = 40 × 5

T - 39.2 = 200

T = 200 + 39.2

T = 239.2N

Therefore, the tension in the rope needed to give the object an upward speed of 3.50 m/s

in 0.700 s is 239.2N

Answer:

The answer is T=592 N

Explanation:

Fw= 392N

a=v/t, so a=3.5ms^-1/0.7s

a=5ms^-2

Fnet=ma

T-Fw=ma

T-392N=40kg(5ms^-2)

T=592N

Answer:

True

Explanation:

Generally speaking, we say that light travels in waves, and all electromagnetic radiation travels at the same speed which is about 3.0 * 108 meters per second through a vacuum.

Answer:

absolutely true

Explanation:

as it travels in a speed of 30×108 m per second