Practice Work-Energy Theorem in Physics
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
The net work done on an object equals the change in its kinetic energy — the bridge between force and motion.
The total work done on an object is exactly what changes its kinetic energy.
Example 1
easyA 4 \text{ kg} box initially at rest is pushed with a net force of 20 \text{ N} over 5 \text{ m}. What is the final speed of the box?
Example 2
mediumA 1500 \text{ kg} car traveling at 25 \text{ m/s} brakes with a friction force of 7500 \text{ N}. How far does it take to stop?
Example 3
mediumA 0.5 \text{ kg} ball moving at 8 \text{ m/s} is hit by a bat that does 25 \text{ J} of work on it. What is the ball's final speed?
Example 4
hardA 2 \text{ kg} block slides down a rough incline (\mu_k = 0.2) of height 5 \text{ m} and length 10 \text{ m}, starting from rest. What is its speed at the bottom? Use g = 9.8 \text{ m/s}^2.