1. Forces and Friction REVIEW

2. Contact Force  a force that acts at the point of contact between two objects.force

3. Gravity  a force which tries to pull two objects toward each other.  It is what keeps you on the ground and what causes objects to fall.  Gravity is what holds the planets in orbit around the Sun and what keeps the Moon in orbit around Earth.

4. Friction  Friction is a force that holds back the movement of a sliding object. force

5. Centripetal Force  is a force that makes a body follow a curved path.

6. Momentum  is the product of the mass and velocity of an object.massvelocity  For example, a heavy truck moving rapidly has a large momentum—it takes a large force to get the truck up to this speed, and it takes a large force to bring it to a stop afterwards. If the truck were lighter, or moving more slowly, then it would have less momentum.

7. Elasticity: Elastic and Inelastic Force  is the ability of solid materials to return to their original shape after being deformed.

8. Force Vectors  A vector is a quantity that has two aspects. X-axis and Y- axis.  Vectors are usually drawn as arrows.  Force is a vector quantity; its units are newtons, N

9. Balance Forces vs. Unbalanced Forces  When two forces acting on an object are equal in size but act in opposite directions, we say that they are balanced forces.  there are no forces acting on it.

10. Muscular Force  force is the force applied using parts of the body like arms or legs.

11. Newton’s 1 st Law  An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.unless acted upon by an unbalanced force  law of inertia.

12. Newton’s 2 nd Law  acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object.net force  F= Mass X Acceleration  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.

13. Newton’s 3 rd Law  For every action, there is an equal and opposite reaction.