Energy Storage Mechanisms

Which of the following is the correct formula for the energy stored in a spring due to it's stretch or compression?

• $E\ =\ -kx$

• $E\ =\ \frac{1}{2}kx^2$

• $E=mgx$

• $E=\frac{1}{2}mx^2$

A force of 20 N compresses a spring with a spring constant of 50 N/m. How much energy is stored in the spring?

• 2 J

• 5 J

• 4 J

• 6 J

• 8 J

The energy stored in an object due to the deformation of the object is called

• Elastic Potential Energy

• Kinetic Energy

• Thermal Enery

• Gravitational Potential Energy

• Chemical Energy

The energy stored in an object due to it's position within a gravitational field is called

• Elastic Potential Energy

• Kinetic Energy

• Thermal Enery

• Gravitational Potential Energy

• Chemical Energy

The energy stored in an object due to it's motion is called

• Elastic Potential Energy

• Kinetic Energy

• Thermal Enery

• Gravitational Potential Energy

• Chemical Energy

A person pushes a box 20 m across a horizontal surface at a constant speed of 0.6 m/s. The box has a mass of 40 kg, and the coefficient of kinetic friction is 0.5. What is the next work done on the box by all the external forces?

• 0 J

• 7.2 J

• 4000 J

• 8000 J

The velocity of a tug boat with a mass of 2000 kg is increased from 2 m/s to 4 m/s over the course of 20 s. What is the net work done on the tug boat?

• 12000 J

• 4000 J

• 600 J

• 16000 J

A hockey puck sliding along frictionless ice with a speed v to the right collides with a horizontal spring and compresses it by 2.0 cm before coming to a momentary stop. What will be the spring's maximum compression if the same puck hits it at a speed of 2v?

• 2 cm

• 2.8 cm

• 4.0 cm

• 5.6 cm

• 8.0 cm

A block slides down a smooth ramp. The block starts from rest at a height h. At the bottom it's moving at a speed v. It then continues to slide up a second smooth ramp. At what height is the speed equal to v/2?

• h/4

• h/2

• 3h/4

• 2h

A wrecking ball is suspended from a 5.0 m long cable that makes a 30 degree angle with the vertical. The ball is released and swings down. What is the ball's speed at the lowest point?

• 7.7 m/s

• 4.4 m/s

• 3.6 m/s

• 3.1 m/s