Potential Energy Physics Example 3

Follow the full solution, then compare it with the other examples linked below.

Example 3

medium
A 0.3 kg0.3 \text{ kg} ball on a compressed spring (k=800 N/mk = 800 \text{ N/m}, compressed 0.15 m0.15 \text{ m}) is released. What speed does the ball reach?

Solution

  1. 1
    Spring PE: PE=12kx2=12(800)(0.0225)=9 JPE = \frac{1}{2}kx^2 = \frac{1}{2}(800)(0.0225) = 9 \text{ J}.
  2. 2
    This converts entirely to KE: 12mv2=9\frac{1}{2}mv^2 = 9.
  3. 3
    v=2×90.3=60≈7.75 m/sv = \sqrt{\frac{2 \times 9}{0.3}} = \sqrt{60} \approx 7.75 \text{ m/s}

Answer

v≈7.75 m/sv \approx 7.75 \text{ m/s}
When a compressed spring releases, its elastic PE converts to kinetic energy. Conservation of energy lets us find the speed without knowing the details of the force during release.

About Potential Energy

Energy stored in a system due to the position or configuration of its parts, ready to be converted into kinetic or other forms of energy.

Learn more about Potential Energy →

More Potential Energy Examples

Example 1 easy

A spring with spring constant [formula] is compressed by [formula]. What is the elastic potential en

Example 2 medium

A spring ([formula]) is stretched [formula]. How much work was done to stretch it?

Example 4 easy

A bungee cord has an effective spring constant [formula]. If it stretches [formula] beyond its natur

← All Potential Energy Examples Potential Energy Concept