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Main » Mechanical Energy » Gravitational Potential Energy » Online ActivityII_4_1

### Gravitational Potential Energy - Online Actvity II.2.1

Gravitational Potential Energy Problems   Include units when entering answers. Ex: for Watts use W or meters per second use m/s. If you enter in a decimal place a '0' to the left of the decimal: Ex: '0.98', not '.98'.

 1. The bob of a pendulum has a mass of 3.0 kg. This bob is pulled sideways so it is 0.95 m above the desk. What is the gravitational potential energy of the bob with respect to the equilibrium position?
2. A 8.3 kg box is at the top of a frictionless incline.
 a) What is the gravitational potential energy of the box with respect to the bottom of the incline?     b) What is the gravitational potential energy of the box with respect to the platform halfway up the incline?
 3 A student lifts a 3.5 kg potted fern from the floor of the Biology room to a counter 0.98 m above the floor. Calculate the change in gravitational potential energy of the potted fern.
4. A roller coaster with a mass of 250 kg is poised at point A.
 a) Calculate the gravitational potential energy at A with respect to the ground.     b) Calculate the change in gravitational potential energy between B and C.
5. What is the gravitational potential energy of a 59.4 kg person standing on the roof of an eight-story building relative to each of the following levels? (Each story is 2.5 m high.)
 a) ground level     b) second floor      c) fifth floor
6. A 2.5 kg rubber ball released from a height of 7.5 m falls to the pavement and rebounds to a height of 6.2 m. Calculate:
 a) the loss in gravitational potential energy during the fall.     b) the gain in gravitational potential energy during the rebound.      c) the net change in gravitational potential energy.
7. 7. Elevator 1500 kg
People in the elevator 620 kg
Floor height 2.7 m
People enter the elevator on the second floor.
 a) the loss in gravitational potential energy during the fall.     b) the gain in gravitational potential energy during the rebound.      c) the net change in gravitational potential energy.
8. Some students at Winter Carnival are tobogganing down a 15 m hill. They start from rest and the force of friction is so small as to be negligible. The mass of the students and the toboggan is 150kg.

 a) Calculate the total mechanical energy of the toboggan at A.     b) Calculate the speed of the toboggan at B.      c) Calculate the speed of the toboggan at C.
9. A Beechnut falls out of a tree 11.0 m above the ground and hits a jogger 2.1 m tall on the top of the head. The nut bounces back up 0.3 m before falling to the ground. If the mass of the Beechnut is 120 g, calculate the gravitational potential energy of the nut relative to the ground at each of the following:
 a) when it in the tree.     b) when it hits the jogger      c) when it bounces up to its maximum height      d) when it lands on the ground      e) when it rolls into a golfer hole and falls 0.75 m to the bottom of the hole