Changes in Motion

Changes in Motion Unit Vocabulary

1.    Force- is a push or a pull. Forces are in action all the time.

2.  Friction- when two objects are rubbed against each other to form heat, light or energy.

3.  1st Law of Newton- an object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon an unbalanced force.

4.  Gravity- a force that pulls any two objects together.

5.  Lubricant-oil or grease used to reduce friction by forming a slippery, thin layer between moving parts.

6.  Pendulum- an object hung from a fixed point that swings freely back and forth under the action of gravity. Example…A swing is an example of a pendulum.

7.  3rd law of Newton- for every action there is an equal and opposite reaction.

8.  Inertia- a property of matter by which it remains at rest or in motion in the same straight line unless acted upon by some external force.

9.  2nd Law of Newton- The second law states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object. The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.

10. Forces and motion are also part of a complicated branch of science, called physics.

11. Weight is the measure of gravity’s force.

12. Contact force is a force between two objects (or an object and a surface) that are in contact with each other.

Last modified: Wednesday, September 12, 2012, 11:16 AM