Kinetic Energy and Work Homework Help

In summary, a 1900 kg car accelerates from 17 m/s to 33 m/s while merging onto a freeway. The engine supplied a power of 7.6 x 105 J and a force of 9500 N. To find the time (T) it took for the car to accelerate, the 80m distance must be taken into account. This information is necessary to solve for the average power (P=W/T) of the car's engine.
  • #1
KTiaam
53
1

Homework Statement



While merging onto a freeway, a 1900 kg car accelerates from 17 m/s to 33 m/s

What power did the engine supply?

W = 7.6 x 105 J
F = 9500 N

Homework Equations



P=W/T

The Attempt at a Solution



Not sure how to find T.
 
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  • #2
KTiaam said:

Homework Statement



While merging onto a freeway, a 1900 kg car accelerates from 17 m/s to 33 m/s

What power did the engine supply?

W = 7.6 x 105 J
F = 9500 N

Homework Equations



P=W/T

The Attempt at a Solution



Not sure how to find T.

Is that the whole problem statement? Are you sure it didn't ask for the average power?
 
  • #3
the previous questions were

a)

how much work was done?

which i found out was 7.6 x 105

b) If the velocity change took 80m of road what average force did the cars energy supply?

which i found out was 9500 N

that was all that was given to me
 
  • #4
KTiaam said:
the previous questions were

a)

how much work was done?

which i found out was 7.6 x 105

b) If the velocity change took 80m of road what average force did the cars energy supply?

which i found out was 9500 N

that was all that was given to me

You left the 80m distance out of your original post. That is the piece of information that you need to figure out how long it took the car to accelerate from v1 to v2 in 80m distance...
 
  • #5


I would approach this problem by first understanding the concepts of kinetic energy and work. Kinetic energy is the energy an object possesses due to its motion, and it is given by the formula KE = 1/2 * m * v^2, where m is the mass of the object and v is its velocity. In this case, the car's initial kinetic energy would be KE = 1/2 * 1900 kg * (17 m/s)^2 = 2.3 x 10^5 J.

Work, on the other hand, is defined as the product of force and displacement. In this problem, the car is accelerating, so the net force acting on it is given by Newton's second law, F = ma, where m is the mass and a is the acceleration. We can rearrange this equation to find the acceleration, a = F/m. Plugging in the given values, we get a = 9500 N / 1900 kg = 5 m/s^2.

Now, we can use the formula for work, W = F * d, where d is the displacement. In this case, the displacement would be equal to the change in velocity, 33 m/s - 17 m/s = 16 m/s. Therefore, the work done by the engine to accelerate the car would be W = 9500 N * 16 m/s = 1.52 x 10^5 J.

Finally, to find the power supplied by the engine, we can use the formula P = W / t, where t represents the time it took for the car to accelerate from 17 m/s to 33 m/s. However, this information is not given in the problem, so we cannot find the exact power supplied by the engine. We would need to know the time or some other information, such as the average acceleration, to calculate the power.

In conclusion, as a scientist, I would suggest that the problem needs to provide more information in order to find the power supplied by the engine. Understanding the concepts of kinetic energy, work, and power is essential in solving problems like this one.
 

What is kinetic energy?

Kinetic energy is the energy an object possesses due to its motion. It is dependent on the mass and velocity of the object.

What is the formula for calculating kinetic energy?

The formula for calculating kinetic energy is KE = 1/2 * m * v^2, where m is the mass of the object and v is its velocity.

How is kinetic energy related to work?

Kinetic energy is related to work through the work-energy theorem, which states that the work done on an object is equal to the change in its kinetic energy. In other words, the work done on an object will result in a change in its kinetic energy.

What are some real-life examples of kinetic energy?

Some real-life examples of kinetic energy include a moving car, a swinging pendulum, a rolling ball, and a person running.

How is kinetic energy affected by mass and velocity?

Kinetic energy is directly proportional to both mass and velocity. This means that as the mass or velocity of an object increases, its kinetic energy will also increase. Similarly, as the mass or velocity decreases, so will the kinetic energy.

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