PhysicsLAB: Work and Energy

How much work (energy) is needed to lift a 200-N object to a height of 4 meters?

How much power is needed to lift the 200-N object to a height of 4 meters in 4 seconds?

What is the power output of an engine that does 60,000 J of work in 10 seconds?

Refer to the following information for the next three questions.

The block of ice weighs 500 newtons.

How much force is needed to push the ice 6 meters up the incline if you neglect friction?

How much work is required to push it 6 meters up the incline?

How much work is required to lift the block vertically 3 meters?

Refer to the following information for the next three questions.

All of the ramps are 5 meters high. From conservation of energy, we know that the KE of the block at the bottom of the ramp will be equal to the loss of PE. Find the speed of the block at ground level in each case.


Case 1	Case 2	Case 3

Case 1

Case 2

Case 3

Refer to the following information for the next two questions.

Which block gets to the bottom of the incline first? Assume no friction.

Which block arrives with the greater speed? Explain your answer.

ABthey have the same speed

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The KE and PE of a block freely sliding down a ramp are shown in only one place in the sketch. Fill in the missing values.

PE top?

KE_{upper middle}?

PE_{lower middle}?

Refer to the following information for the next four questions.

A big metal bead slides due to gravity along an upright friction-free wire. It starts from rest at the top of the wire as shown in the sketch. How fast is it traveling as it passes:

Point B?

Point D?

Point E?

At which point does it have its maximum speed?

Refer to the following information for the next question.

Rows of wind-powered generators are used in various windy locations to generate electric power.

Does the power generated affect the speed? Would locations behind the "windmills" be windier if they aren't there? Discuss this in terms of energy conservation with your classmates.