Lesson 5.5

A pair of dogs are walking on a treadmill at a constant velocity. Which statement best describes whether or not the corgi's are doing work?

• The dogs will eventually get tired, so work is being done.

• The dogs are enjoying themselves so they are no work is being done.

• The dogs are applying force to the treadmill, so there is work being done.

• The velocities of the dogs are not changing, so the net work done is 0J

Answer explanation

This question links to success criteria: I can relate work and changes in kinetic energy.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

Which of the following best describes the work that is done in the image?

• When the cat pushes against the bed it does work to jump forward.

• When the cat is moving forward it does work to change its position

• When the cat jumps off the bed, the bed does work to remain stationary

• No work is done in this video because no money is shown in the video.

Answer explanation

This question links to success criteria: I can relate work and changes in kinetic energy.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

At the bottom of the slope, the skier starts with 35,000 J f Kinetic energy. Watch the animation and identify which of the following statements shows how much work the unpacked snow does on the skier.

• 15,000 J of work is being done in the positive direction

• 35,000 J of work is being done in the negative direction.

• 50,000 J of work is being done in the negative direction

• 0 J of work is being done. The skier is clearly on vacation.

Answer explanation

This question links to success criteria: I can relate work and changes in kinetic energy.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

• 33,072 J of work is being done by gravity.

• 1,036.75 J pf work is being done by gravity

• 1,074,850.56 J of work is being done by gravity

• 0.0000076 J of work is being done by gravity.

Answer explanation

This question links to success criteria: I can relate work and changes in kinetic energy.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

The steam engine on an old river boat burns coal to release 13,942 J of energy. If 11,938 J of heat are wasted in the process, how much work did the engine do?

• 0.86 J of work

• 2004 J of Work

• 11,938 J of work

• 25,880 J of work

Answer explanation

This question links to success criteria: I can relate heat generated, work done and waste energy in a heat engine.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

An old fashion train burns fuel to produce 17,524 J of energy. If it does 3,785 J of work, how much waste heat was produced?

• 4.63 J of waste heat

• 11,938 J of waste heat.

• 13,739 J of waste heat

• 21,309 J of waste heat

Answer explanation

This question links to success criteria: I can relate heat generated, work done and waste energy in a heat engine.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

A new steam engine is being tested. When the engine runs it produces 6,543 J of waste heat and 2,109 J of work. What was the total input energy of the engine?

• 8652 J of energy

• 4434 J of energy

• 0.32 J of energy

• 3.10 J of energy

Answer explanation

This question links to success criteria: I can relate heat generated, work done and waste energy in a heat engine.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

The steam engine on an old river boat burns coal to release 12,345 J of energy. If the engine produces 6789J of work, what was the efficiency of the engine?

• 75 %

• 25 %

• 189%

• 55%

Answer explanation

This question links to success criteria: I can determine the efficiency of a heat engine based on work done and heat generated.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

An old fashion train with an efficiency of 25% burns fuel to produce 16,000 J of energy. How much work does it do?

• 20,000 J of work

• 640 J of work

• 12,000J of work

• 4000 J of work

Answer explanation

This question links to success criteria: I can determine the efficiency of a heat engine based on work done and heat generated.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.

How much energy was needed at the start if a jet engine with an efficiency of 89% produces 10,000J of work?

• 10,000 J

• 8,900 J

• 11235.96 J

• 9,911 J

Answer explanation

This question links to success criteria: I can determine the efficiency of a heat engine based on work done and heat generated.

If you got it correct place a check mark in the question results section. If you got it incorrect place an X in that section. If this was a redemption question, cross out the one X and replace it with a check mark.