Ignacio has several balls of the same size. each ball is made of a different material, and each ball has a different mass. ignacio
rolls one ball down a ramp, then measures how long it takes the ball to roll one meter after it reaches the bottom of the ramp. he
then repeats this with each ball.
in this experiment, which variable is changed by the investigator?
a. the time it takes the ball to travel one meter
b. the distance traveled by each ball
c. the height of the ramp
d. the mass of the ball