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## Work

Work transfers energy to a system through the forceful manipulation of its state. Do some work on yourself to master this fundamental mode of energy transfer.

# Warmup

Ben wants to ascend to height $$h$$. He has two choices:

He can either climb a ladder or he can walk up a slope.

In which case would Ben do more work against gravity?

When an airplane lands on a runway, its speed decreases very quickly and it soon comes to a halt. What is the sign of work done by all the forces acting on the plane when it lands?

Frank tied a string to his toy car and wants to pull it along with him as he walks along his room. He can pull the toy car with a force of $$\SI{5}{\newton}$$

At what angle should he pull the string so that he does maximum work on the toy car?

John observed the motion of the football and said:

Gravity is doing negative work on the football

Assuming John is correct, what can we conclude from John's statement?

Alice climbed the red ladder in 5 seconds, and the blue ladder (which is twice as long) in 10 seconds.

Did she spend more energy climbing the red ladder, or the blue ladder?

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