Gravity and Motion Newton and THE Apple

Falling Objects Free Fall- occurs when an object is ONLY affected by gravity. Terminal Velocity- occurs when an object falls at a constant velocity is reached when the force of gravity is EQUAL to the force of air pressure. Air Resistance- amount of air resistance depends on the objects size and shape. The greater the surface area the greater the air resistance. Rate at which an object falls- is NOT affected by mass if we dropped 3 different balls with different masses, they will land at the same time.

Newton’s Laws of Motion Newton’s First Law- an object at rest remains at rest, and an object in motion remains in motion unless acted upon by an unbalanced force. This is also called the Law of Inertia. Inertia- the tendency of an object to resist change Unbalanced Forces allows an object to accelerate ex. A car changes direction, but you the passenger move forward, but you end up pressed against the side of the car. SI unit of measurement is kg/m/sec2

Newton’s First Law

Newton’s Second Law The acceleration of an object depends on the mass of the object and the amount of force applied. It is easier to push an object that has a smaller mass and a smaller force in order to get the same acceleration as a larger object. Big car vs. Smaller car Large mass objects will have the least amount of acceleration, AND take longer to stop. Think of an 18 wheeler on the highway.

Newton’s Third Law of Motion Whenever one object exerts force on a second object, the second object exerts an equal AND opposite force on the first object. For EVERY action, there is an EQUAL and OPPOSITE reaction. Forces act in pairs. You sit in a chair, one force is pushing your body down on the chair, but the chair is pushing up on your body. This is called the Reaction Force.

Momentum Depends on both the mass and velocity of an object. The greater the mass, the greater the momentum. As velocity increases, momentum will also increase. Ex. Passenger train Ex. Running into a person who is standing still causes the other person to be knocked down.

Conservation of Momentum The momentum BEFORE a collision is EQUAL to the momentum AFTER the collision. When 2 objects stick together after a collision the velocity will decrease in the first object. An object has more momentum than another object because it has a larger mass, even if it has the same velocity.

Collisions and Explosions Elastic Collision- 2 objects colliding and then moving as 2. a larger mass object collides with a smaller mass object the smaller mass object will have a faster velocity Inelastic Collison- 2 objects colliding and moving as 1 object. Explosion- occurs when there is one object moving as one, then will move as 2 separately.

Conservation of Momentum

Space X Explosion https://www.cnbc.com/2016/09/02/elon-musk-says-rocket-did-not- explode-but-instead-experienced-a-fast-fire.html