Variables Affecting Motion Practice Test

A student investigates: How does starting height on a ramp affect a toy car’s speed at the bottom? The student wants to be sure changes in speed are caused by height, not something else. Which variable should be controlled (kept the same)?

A student investigates: How does the mass of a cart affect how fast it rolls down a ramp? The student will add different masses to the same cart and release it from the same starting point on the ramp each time. Which variable is the independent variable in this investigation?