Practice Conservation of Energy in Physics
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
Energy cannot be created or destroyed, only transformed from one form to another.
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.