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Spring Launchers

Part of the Mechanics section of Coddy's Physics journey. Lesson 59 of 94.

A squeezed spring can launch an object. On a smooth, level surface all its elastic energy becomes kinetic energy:

½ k x² = ½ m v²

Before: a ball rests against a spring compressed by x at a wall. After: the spring is back at its natural length and the ball moves away with speed v

The spring pushes the ball until it reaches its natural length.

The object leaves the spring at its natural length, at top speed. Twice the squeeze gives twice the launch speed.

Energy bars: before release 4 joules of elastic energy in the spring and no kinetic energy, after release no elastic energy and 4 joules of kinetic energy in the ball

The 4 J in the spring becomes 4 J of kinetic energy.

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Challenge

A toy dart gun fires a 0.02 kg dart at 5 m/s from a spring squeezed 0.05 m. Find the spring constant k.

Try it yourself

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This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Mechanics