Building a test ramp
You will need to build a ramp to provide your cart an equal start, again and again.
Cut a piece of cardboard about 1m long and at least 30cm wide.
Mark two lines 5cm from each side of the cardboard.
Along the two lines, fold the cardboard into a "U" to make the edges stiff and keep the cart from running off the edge.
Then the cardboard ramp rests easily on a flat surface.
To use the ramp, you will need to prop one end up with books. One simple way to measure the slope of the ramp is to give the ratio of the height of one end to the length. Thus, if the ramp end is raised 10cm and it is 1 meter long, its slope is about 1:10, or 10 percent. Don't raise it much more than this. The cart will go too fast!
HINT:How should you measure how far "up" the cart is when you release it? The distance along the ramp from its bottom edge to the rear wheels of the cart is a good measure.
Experiment with different slopes and distances up the ramp. How do slope and distance affect how far the cart will roll? What arrangement is the best for testing the friction of the cart? Write your thoughts in Notes on your handheld computer.
