Background

​The concept of energy is central here.  When we do work we are expending energy.  When a body is travelling at speed is has kinetic energy due to its speed.  When an object is at a height above the ground it has energy, called potential energy that can be realised by letting the object fall.  Commonly one form of energy can appear in a different form.  When we push a car up hill, we expend energy on the car which gains potential energy.  We expect that in ideal conditions energy will be conserved.  We don't see this in practice because there are usually ways in which energy escapes from the system, typically there may be work against friction which heats surfaces, energy might be converted to sound, or might raise the temperature of something.  For example, in a waterfall, the water at the top has potential energy it falls and gains kinetic energy, it then lands in the pool at the bottom where it loses its kinetic energy which heats the water.  So, the temperature of the water at the top of a waterfall is lower than that at the bottom.

In this scenario we are going to only consider the ideal case, where there are no losses to friction and other possible energy leaks.  As all these different forms of energy are measured using the same units 'Joules' (J).

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Notice that the yellow car is high on the ramp at the left.

Press ‘Start’, the car will start to roll down the ramp, then up and over the hump, and up the final slope where it will be halted.

You can see the car’s speed and height at any point on the central speedometer and height meter.

You can see the unbroken beam in the screenshot above and the beam of light being broken by the car in the screen shot below.