Add weight to the cart. Does that affect its final velocity? Do you think a heavier cart has more energy than a lighter cart, when they're going at the same speed? Where does the additional energy come from?

How are potential energy and kinetic energy related as the cart rolls down the ramp? To find out, place the cart with the back wheels at the bottom of the ramp and start recording both velocity and position. By hand, roll the cart up to the top of the ramp and let it roll back down the ramp. After collecting your data, pick five times and mark them both on both the velocity and the position graphs. One mark should be at the top and one just as the cart reaches the bottom of the ramp. The others should be various times between these end points.

Calculate the PE and KE (refer to the formulas below) at each of these times. In this case, the height of the cart in the formula for PE is the height straight up above the floor. It is equal to the slope of the ramp times the position reading. Add the PE and KE together. Does the sum remain constant? Should it remain constant?

To calculate the cart's potential energy (PE) and kinetic energy (KE). Use these formulas.

PE (joules) = mass(kg) * 9.8(m/s*s) * height(m)

KE (joules) = 0.5 * mass(kg) * velocity(m/s) * velocity(m/s)

Use the Force probe to measure the mass (weight/9.8 (m/s*s) of the cart. The height of the cart is the distance up the ramp times its slope (height of the ramp/length of the ramp).