KE and PE Experiment Track

Quick Answer: The KE and PE Experiment Track is an inclined ramp for studying the conversion of gravitational potential energy into kinetic energy. The listing image shows a metal channel track on a supporting frame with several release positions and a steel ball; the ball is let go from a measured height and its speed at the bottom is compared with the energy it lost.

From Height to Speed

A ball held at height h above the bottom of the ramp has gravitational potential energy mgh. As it rolls down, that energy turns into kinetic energy, so at the foot of the track the ball moves at its fastest. If no energy were lost and the ball simply slid, its speed would be v = √(2gh), whatever its mass. The KE and PE experiment track lets students test how closely a real ball follows that prediction.

A rolling ball falls short of it for a well-understood reason: part of its energy goes into spinning. For a solid sphere rolling without slipping, only five-sevenths of the lost potential energy appears as forward motion, so the expected speed is √(10gh/7). Friction, air resistance and sound take a little more. Comparing measured speeds with both predictions turns a simple ramp into a useful discussion of energy stores and dissipation.

The speed at the bottom can be found by timing the ball over a measured flat distance after the ramp, with light gates if the school has them, or by letting it leave the edge of a bench and measuring how far it travels before landing. The number of height settings and the track length should be confirmed when ordering.

Specifications

Care & Handling

• Place the track on a stable, level bench and stop the ball with a soft catcher at the foot.
• Wipe the channel clean before trials; grit or dust makes the ball bounce and lose energy.
• Keep the steel ball dry to prevent rust spots that roughen its surface.
• Store the ball in a pouch or box, since a loose ball rolling off a bench can damage floors or trip someone.

Applications

• Calculating gravitational potential energy and kinetic energy from measurements
• Testing whether final speed depends on release height but not on mass
• Introducing rotational kinetic energy at senior secondary level
• Projectile experiments using the ball’s launch from a bench edge

Why Choose LabEquip

Science departments buy this track for the energy topic because it produces real numbers for mgh and ½mv² in one practical. LabEquip supplies it in the STEM kits range, and the Loop-the-Loop Physics Model takes the same energy idea into circular motion. Send order details via the contact page.

Frequently Asked Questions

Why is the measured speed lower than the square root of 2gh?

That formula assumes all the potential energy becomes forward kinetic energy. A rolling ball also spins, and for a solid ball two-sevenths of the energy goes into rotation. Friction, air resistance and small bounces take the measured speed a little lower again.

Does the mass of the ball affect its speed at the bottom?

In the ideal case, no. Both potential energy and kinetic energy are proportional to mass, so mass cancels out. A heavier steel ball of the same size reaches practically the same speed, which surprises many students.

How can I measure the speed of the ball?

Time the ball over a measured length of flat track or bench after the ramp and divide distance by time. Light gates give more precise times. Alternatively, let the ball roll off a bench edge and use the landing distance and bench height to calculate the launch speed.

Where does the missing energy go?

It is dissipated mainly as heat through friction between ball and track, as sound when the ball rattles, and as work against air resistance. The total energy is still conserved; it is just spread into forms that no longer contribute to the motion.

What happens when the release height is doubled?

The potential energy doubles, so the kinetic energy at the bottom roughly doubles. Because kinetic energy depends on speed squared, the speed rises by about 1.4 times, not twice. Plotting speed squared against height gives a straight line.

Can the ball ever finish with more energy than it started with?

No. The kinetic energy at the bottom can at most equal the potential energy lost, and measurements always come out slightly lower. If the ball rolls up a second ramp, it climbs to a little less than its release height, never higher.

Last Updated: September 2026