The driver of a 3000 lb. car, coasting down a hill, sees a red light at the bottom, and must stop. His speed when he applies the brakes is 60 mph, and he is 100 feet (vertically) above the bottom of the hill. (a)How much energy as heat must be dissipated by the brakes if we neglect wind resistance and other frictional effects

Answers

Answer 1

Answer:

Explanation:

60 mph = 60 x 1760 x 3 / (60 x 60) ft /s

speed of car , v = 88 ft /s

kinetic energy of car = 1/2 m v²

= .5 x 3000 x 88²

= 11616 x 10³ poundal - foot

Potential energy = mgh

= 3000 x 32 x 100

=  9600 x 10³ poundal - foot

Total energy = potential energy + kinetic energy

= ( 11616 + 9600 )x 10³

= 21216 x 10³ poundal - foot .

This energy is dissipated as heat when brakes are applied on the car to stop the car .


Related Questions

The Moon has a smaller mass than the Earth. If you were to travel to the moon your weight would....
A Increase
B Decrease
C Stay the Same
D Vary with day and night

Answers

Answer:The Moon has a smaller mass than the Earth. If you were to travel to the moon your weight would..

Explanation: It would decrease.

The Moon has a smaller mass than the Earth. If you were to travel to the moon your weight would decrease because the acceleration due by gravity on the moon is less than the acceleration due to gravity on the earth, therefore the correct answer is option C.

What is gravity?

It can be defined as the force by which a body attracts another body towards its center as the result of the gravitational pull of one body and another.

In comparison to the Earth, the Moon is less massive. Your weight would drop if you traveled to the moon because the acceleration caused by gravity there is lower than that caused by gravity here on Earth.

As a result of the less gravity on the moon, the weight would decrease.

Thus, the correct answer is option C.

To learn more about gravity from here, refer to the link;

brainly.com/question/4014727

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HELP ASAP PLS

A balloon with a positive charge will stick to a wall that has a negative charge.
What force causes this?
A. Gravity
B. Electric force
C. Magnetic force
D. Air gesistance

Answers

Answer : B. electric Force

The reason that the balloon will stick to the wall is because the negative charges in the balloon will make the electrons in the wall move to the other side of their atoms (like charges repel) and this leaves the surface of the wall positively charged.


If I’m wrong I’m sorry :(

Based on the data, which statement describes the most reliable way to
encode and transmit data and tells why?
A. Digital waves are more reliable because they are less likely to
change when copied.
B. Analog waves are more reliable because they include a range of
values like the original.
C. Analog waves are more reliable because they are less likely to
change when copied.
D. Digital waves are more reliable because they are slightly different
from the original.

Answers

Answer:it’s A. right for ape x

Explanation:

Based on data, digital waves are more reliable because they are less likely to change when copied (Option A).

What is a wave?

A wave is a periodic distortion capable of traveling through a suitable media (either air or water).

The waves can be classified according to their direction into transversal and perpendicular.

In conclusion, based on data, digital waves are more reliable because they are less likely to change when copied (Option A).

Learn more on waves here:

https://brainly.com/question/15663649

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Which of the following is NOT a characteristic of noble gases?

unreactive
odorless
solid at room temperature
colorless

Answers

solid at room temperature
I think it’s Solid at room temperature

There is a very long straw of charge that is uniformly charged in electro static equilibrium. It has a charge per unit length of 4.0E-9 C/m (4.0 nC/m) and a radius of 0.5 m. What is the strength of the electric field a distance of 10.0 m from its center outside the straw

Answers

Answer:

2880 N/c

Explanation:

Given that:

Charge per unit length ; λ = 4 * 10^-9

radius, r = 10

Radius, R = 0.5m

Using the relation :

2λr / 4πE0R²

Columb's constant, k = 1/4πE0 =. 9* 10^9Nm²/C²

Hence, we have :

2λrk/ R²

(2 * 4 * 10^-9 * 10 * 9 * 10^9) / 0.5^2

(720 ÷ 0.25)

= 2880 N/c

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