Question

Which does heat represent?
A. transfer of kinetic energy
B. transfer of thermal energy
C. transfer of potential energy
D. transfer of temperature
@Destinymasha @linn99123

Answer 1

@Vonte12 @Awesome781

Answer 2

transfer of temperature

Answer 3

another @lhteshamMalik

Answer 4

yup

Answer 5

How does a pulley make it easier to load cargo onto a cargo ship?

A. The pulley increases the force needed to lift the load by moving it over a shorter distance. It also changes the direction of the force. As the input force is applied upward, the output force is exerted downward.

B. The pulley reduces the force needed to lift the load by moving it over a longer distance. It also changes the direction of the force. As the input force is applied downward, the output force is exerted upward.

C. The pulley reduces the force needed to lift the load by moving it over a shorter distance. It also changes the direction of the force. As the input force is applied upward, the output force is exerted downward.

D. The pulley increases the force needed to lift the load by moving it over a longer distance. It also changes the direction of the force. As the input force is applied downward, the output force is exerted upward.

Answer 6

B?

Answer 7

@IhteshamMalik

Which describes the difference between a bowling ball sitting in the rack waiting to be used and the bowling ball knocking pins down?

A. In the rack, the bowling ball has no energy at all. As it knocks down the pins the energy is 75% kinetic and 25% potential.

B. In the rack and when knocking down pins, the potential energy and the kinetic energy of the bowling ball are equal.

C. In the rack, the bowling ball has only potential energy. As it knocks pins down, its potential energy has decreased, while its kinetic energy has increased.

D. In the rack, the bowling ball has only kinetic energy. As it knocks pins down, its potential energy has increased, while its kinetic energy has decreased.

Answer 8

IDK, I'm no good at science.

Answer 9

I typed it exactly as my homework says. :)

Answer 10

Okay i searched very much... and i am 80% agree with the 3rd statement....... C. have potential energy.... after hitting the pins p.e decreased and k.e increased.

Answer 11

Sir @PsiSquared check this statement please.... it was a little confusing... do you agree with me?

Answer 12

Heat is energy. It's not really the transfer of anything, so I'm not sure what they are even asking. Temperature is a measure of heat. On a micro scale, you can think of temperature as a measure of the average kinetic energy of the particles in a substance. The faster they are moving, the more energy they impart to the thermometer.

The pulley question is B. A pulley requires you to use less force, but to apply that force over a larger distance. And it changes the direction of motion. If you are lifting something upwards, a pulley allows you to apply your force downwards (you pull down on the rope, and whatever else goes upward).

Answer 13

Yes, the answers are poorly worded. The best answer is C. Assuming that the bowling can go now lower in elevation, all of the energy in the bowling ball when it hits the pins should be kinetic. It should have no potential energy.

Answer 14

Heat is an energy transport mechanism. I think that is what the first problem is trying to state. It just does so poorly. The units of heat are therefore the same as the units of energy. It transfers energy along a thermal gradient, but it does transfer temperature. The correct answer for the first question is B.

Answer 15

Yes, it can be argued that at its most basic level, thermal energy is the same as molecular kinetic energy, but thermal energy is the better answer because it identifies a specific type of kinetic energy.

Answer 16

@IhteshamMalik Excuse me? This is EXACTLY how y teacher put it.

Answer 17

I'm not sure what you mean by maximum force. A pulley is a simple machine that makes it so you can use less force to achieve the same amount of work.

Work = Force x Distance

A pulley lowers the force that you need to use, but the above equation means that you MUST increase the distance over which that force is applied.

Answer 18

@Vandreigan right.... force increases at minimum distance.... .

Answer 19

As for the pulley, consider the work equation:\[W=Fd\]where W is work; F is force; and d is distance. In an ideal system, whether you use a pulley or not, you will do the same amount of work. Looking at the equation. If we shorten the distance over which the work is done, the force has to increase. Likewise, if we increase the distance over which work is done, the force has to decrease. This is why when you use a pulley, you have to pull more rope as the mechanical advantage of the pulley system goes up. In other words, if the pulley has an MA of 5, you would pull more rope than you would with a pulley with MA=3, but you would exert less force.

Answer 20

@CrazyCountryGirl now have you clear answers of all the questions??

Answer 21

@PsiSquared and @Vandreigan thanks a lot to both of you.... :)

Answer 22

" B. The pulley reduces the force needed to lift the load by moving it over a longer distance. It also changes the direction of the force. As the input force is applied downward, the output force is exerted upward."

I'm not sure what you are trying to say. Option B clearly says what it needs to say, with the possible confusing wording of "by moving it over a longer distance." I assumed they just meant that the force was applied over a longer distance, as the others seem terribly incorrect, with the exception of C, whose major flaw was that using a classic pulley system, you pull downward on a rope to lift something upwards.

Answer 23

Yes its right... B option

Answer 24

And it was my pleasure :)

Answer 25

You're welcome.

Answer 26

Which compares the thermal energy found in a piece of coal with the thermal energy found in a newly opened coal mine?

A.
The amount of thermal energy is directly related to the potential energy of a substance's particles. A piece of coal has fewer total particles than a newly opened coal mine. Therefore, the piece of coal has less thermal energy.

B.
The amount of thermal energy is directly related to the kinetic energy of a substance's particles. A piece of coal has fewer total particles than a newly opened coal mine. Therefore the piece of coal has less thermal energy.

C.
The amount of thermal energy is directly related to the potential energy of a substance's particles. The particles in a piece of coal are more concentrated. Therefore, the piece of coal has more thermal energy than the newly opened mine.

D.
The amount of thermal energy is directly related to the kinetic energy of a substance's particles. The particles in a piece of coal are more concentrated. Therefore, the piece of coal has more thermal energy than the newly opened mine.