Practice Conservation of Energy in Physics
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
A fundamental law of physics stating that the total energy of an isolated system remains constant over time — energy can be transferred between objects.
Energy is like money—you can spend it, save it, or change its form, but you can't make more out of nothing.
Example 1
mediumA 2 \text{ kg} ball is dropped from 20 \text{ m}. What is its speed just before hitting the ground? Use g = 10 \text{ m/s}^2.
Example 2
hardA roller coaster car (500 \text{ kg}) starts from rest at 30 \text{ m} high and descends to 10 \text{ m}. What is its speed at 10 \text{ m}? Use g = 10 \text{ m/s}^2.
Example 3
mediumA pendulum of length 2 \text{ m} is released from a height 0.5 \text{ m} above its lowest point. What is its speed at the lowest point? Use g = 10 \text{ m/s}^2.
Example 4
hardA skier (60 \text{ kg}) starts from rest at the top of a 25 \text{ m} hill and reaches the bottom at 18 \text{ m/s}. How much energy was lost to friction? Use g = 10 \text{ m/s}^2.