# SAT II Physics : Definitions of Acceleration, Velocity, and Displacement

## Example Questions

### Example Question #1 : Definitions Of Acceleration, Velocity, And Displacement

A model rocket, launched vertically, travels upwards  and falls to the ground. At what point during flight is the rocket's acceleration greatest?

Possible Answers:

At the highest point of the flight

The answer cannot be determined from this information

The acceleration remains constant throughout the flight

Just after launch

Just before landing

Correct answer:

The acceleration remains constant throughout the flight

Explanation:

Newton's second law tells us that force and acceleration are directly related; if there is an acceleration, then there is also a force. This principle can help conceptualize this question.

While the rocket is in the air, there is only one force acting on it: the force of gravity. We can thus conclude that the acceleration of the rocket is directly related to this force. Since the force on the rocket (the force of gravity) is constant, its acceleration is also constant.

Any object that is in projectile or free-fall motion will experience a constant acceleration due to gravity.

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