Joe is interested in observing how the height of a ramp affects the speed of his toy car when he releases it at the top of the ramp. He sets up 3 ramps, one at a 15 cm from the ground, one at 20 cm, and one at 25 cm. He then times how long his car takes to travel a specific distance from the time he releases it. He determines that the car has the greatest speed when the ramp is 20 cm off the ground. Use this information to answer Questions 6-8 below:
6.
What is the independent variable in this experiment?

7.
What is the dependent variable in this experiment?

8.
How many treatments did Joe have?

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.

Ithink it is letter b, i may be wrong but i think that is the answer