1. Force and Motion The only reason an object changes it velocity is because a force acts on the object. Remember a change in velocity can be either a change in speed (such as a car going faster) or the object changes direction (a rock in a sling spinning around somebody’s head)

2. Vocabulary Mass: the amount of matter in an object and is constant; measured in kg (kilogram) Weight: the amount of force applied by gravity to an object; measured in Newtons (N) or pounds (lb) Normal force: the amount of force applied perpendicular to the surface of contact; measured in Newtons (N)

3. Vocabulary Constant: Remains the same Acceleration: a change in velocity; measured in meters per second per second (m/s²) Inertia: a property of matter that resists a change in motion and is directly related to mass

4. Newton and the 3 Laws of Motion 1 st Law of Motion (Law of Inertia) – A body will remain in a state of constant motion unless acted on by an unbalanced force – That means a body will remain at rest or continue in a straight line at constant speed unless a force is applied to the object

5. Newton and the 3 Laws of Motion Newton 2 nd Law of Motion (Law of Force and Acceleration) – An object will accelerate in the direction of the force applied to it – This means things move in the direction that it is pushed or pulled. – The Formula: Force=mass x acceleration (F=m*a)

6. 2 nd Law continued Force is directly proportional to mass and acceleration – This means the force will increase if either mass or acceleration increases – If the force is constant, mass and acceleration are inversely proportional to each other.

7. Newton and the 3 Laws of Motion Newton’s 3 rd Law (Law of Action/Reaction) – For every action there is an opposite and equal reaction force – This means that if you press on your desk, the desk pushes back – Remember that things move because of unbalanced forces.

8. Newton and the 3 Laws of Motion Forces are generally considered pushes or pulls and are measured in Newtons (N) kgm/s² Special forces – Tension is the force that is found when a elastic object is pushed or pulled – Normal force: the amount of force applied perpendicular to the surface of contact; measured in Newtons (N)

9. Newton and the 3 Laws of Motion Friction is a either considered static or kinetic – Static friction keeps an object from moving even if a force is applied (pushing a book off a desk) – Kinetic friction occurs once an object is moving and this friction slows an object down (a car coming to rest at a stop sign) – Air resistance is a type of friction caused by the earth’s atmosphere