motion

1. velocity

1.1. To have a constant velocity, an object must have a constant speed in a constant direction

1.2. the car you drive has to have velocity

1.3. nascar

2. gravity

2.1. a force that keeps a object on the ground

2.2. the thing that keeps us on the ground

2.3. suction

3. friction

3.1. the resistance that one surface or object encounters when moving over another

3.2. metal on metal

3.3. heat

4. acceleration

4.1. the increase in speed

4.2. to get faster

4.3. throttle cable

5. force

5.1. strength or energy as an attribute of physical action or movement

5.2. to make something move

5.3. hammer

6. speed

6.1. the rate at which someone or something is able to move or operate

6.2. how fast something moves

6.3. nascar

7. distance

7.1. an amount of space between two things or people

7.2. the area between to objects

7.3. miles

8. time

8.1. A time and motion study (or time-motion study) is a business efficiency technique

8.2. the distance between two events

8.3. clock