Work & Power
PE & KE
EPE
Conservation of Energy
100

20 J of work is done in 60 seconds of jumping rope. What was the power required?

0.33 W

100

What is the kinetic energy of a 158 kg sea turtle swimming at 0.42 m/s?

13.9 J

100

A spring is compressed 4 cm. If its spring constant is 300 N/m, how many Joules of energy are stored in it?

0.24 J

100

A 64 kg woman on a 10 kg bike accelerates from 4 m/s to 8 m/s. How many Joules of work were done to change the speed of her and her bike?

1776 J

200

How much work is required to lift a 130 kg barbell 0.8 meters?

1020.24 J

200

A 0.9 coconut falls from a tree. If the GPE of the coconut is 22.05 J, what is the tree's height in meters?

2.50 m

200
A scrunchie with k=40 N/m is stretched 30 centimeters. How many Joules of elastic potential energy are stored in the spring?

1.8 J

200

A 2 kg toy car is moving at a velocity of 1.5 m/s. What is the cars total mechanical energy?

2.25 J

300

If 12 J of work is done lifting a 0.62 kg basketball vertically, how high was it lifted?

1.97 m

300

A 113 kg sea turtle traveling across the Pacific has a KE of 2.26 J. What is its speed?

0.2 m/s

300

How many meters would one need to stretch a spring (k=50 N/m) for it to store 38 J of energy?

1.2 m

300

A 500 kg roller coaster starts from rest from the top of a 45 m hill. What is the speed of the roller coaster when it reaches a height of 15 meters?

24.26 m/s

400

A runner exerts 250 Watts of power in 16 minutes. How much work was done in this time?

240,000J

400

A beach volleyball is tossed in the air. If the ball has a PE of 8.23 J at its maximum height of 3 meters, what is the ball's mass?

0.28 kg

400

A bungee cord is displaced 25 meters when 80 N of force is applied to it. What is the spring constant of the cord?

3.2 N/m

400

A 2 kg bowling ball is dropped from rest from the Eiffel Tower at a height of 10 meters. If air resistance does -150 J of work on the bowling ball as it falls, what is its final velocity right before it hits the ground?

6.78 m/s

500

A quarterback gets hit while throwing, and the football is thrown straight up with a velocity of 10 meters per second. If the quarterback exerted 50 Watts of power to throw the ball, what is the mass of the football?

0.51 kilograms

500

A wave tosses a 64 kg surfer 1.2 meters in the air. What will his speed be right before he hits the ground?

4.85 m/s

500
An archer pulls back an arrow on the string of their bow so that it is displaced 0.50 meters. If this requires 31.25 J of work, what is the spring constant on the bow?

250 N/m

500

A 2 kg toy car is moving at a constant velocity of 1.5 m/s when a child does 2 N of work on the car to speed it up. What is the cars final velocity?

2.1 m/s

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