A set of pulleys is used to raise a 200 N crate 5 m. to fo this the operator applies a force of 50 N and pulls in 25 m of rope. Find the efficiency of the pulley system.

A: 50%

B: 62.5%

C: 75%

D: 80%

Two rods are both precisely 10.000 cm long. Rod "A" is made of aluminum, while Rod "B" is made of steel. The linear expansion coefficient "alpha" is twice as large for aluminum (24 x 10^-6 K^-1) than for steel (12 x 10^-6 K^-1).

A hydroelectric dam holds back a lake of surface area 3.0*106m2 that has vertical sides below the water level. The water level in the lake is 150 m above the base of the dam.

Jacob has a bucket of ice. He covers the bucket with a lid and sets it in the sun. The ice melts into liquid water. How does the mass of the ice compare with the mass of the water? A. The mass of the ice is the same as the mass of the water. B.

If a heat engine takes in 4565 kJ and gives up 2955 kJ during one cycle, what is the engine's efficiency?

This type of burn results from high temperatures caused by an electric arc or explosion near the body

Based on how the book describes a heat pump in sec 16.3 how does a heat pump prove law of conservation of energy

When a gas in a container is squeezed to half its volume, its density?

A ballet student with her arms and a leg extended spins with an initial rotational speed of 0.90rev/s. As she draws her arms and leg in toward her body, her rotational inertia becomes 0.80 kg⋅m2 and her rotational velocity is 4.1rev/s.

The power rating of a vacuum cleaner is 0.8 kilowatts. If you use the vacuum cleaner for 2.5 hours, how much energy does it use?

Which has more gravitational potential energy - - a cliff diver at the top of the cliff or a cliff diver at the bottom of the cliff?