**SYSTEM IN MOTION**

**Select the correct term to complete the sentences.**

**centripetal force**

**range**

**center of gravity**

**rotates**

**displacement**

**parabola**

**revolves**

**satellite**

**projectile**

**trajectory**

**center of mass**

**angular speed**

**law of universal gravitation**

**1. A _____ vector shows an object’s change in position.**

**2. The path of a projectile is its _____.**

**3. A _____ is an object that moves through the air only affected by the**

**force of gravity.**

**4. The mathematical shape of a projectile’s trajectory is a _____.**

**5. The horizontal distance a projectile travels is its _____.**

**6. An object _____ when it moves in a circle around an external axis.**

**7. A wheel ____ about an axis in its center.**

**8. _____ is the measure of how fast an object rotates or revolves.**

**9. An inward _____ is needed to move an object in a circle.**

**10. The _____ describes the relationship between mass, distance, and**

**gravitational force.**

**11. An object that orbits the earth is a _____.**

**12. An object’s _____ is the average position of all the particles that**

**make up its mass.**

**13. You can balance an object on your finger if you support it at its**

**_____.**