For his science fair experiment, Cole decided to determine how different types, of surface material, affect how fast a matchbox car will go. He chose to use a tile floor, concrete patio and carpet. He
used the same car for each of the 20 trials. He measured the distances the car went after riding
down a 1-meter ramp.
what is the independent variable?
what is the dependent variable?
what is the constant for each trial?