Good Morning Come in quietly….KEY WORD QUIETLY Turn in Signed Progress Report Copy down homework Complete Bell Ringer

Today we will Explore Terminal velocity, Free Fall, and Projectile Motion Take Notes Quick Activity

If I dropped a marble and a tennis ball, which would land first?

Objects fall to the ground at the same rate because acceleration due to GRAVITY is the same for all objects. All objects accelerate toward earth at a rate of 9.8 meters per second/second. This means for every second that an object falls, the velocity increases 9.8 meters per second.

Air Resistance Air resistance is the force that opposes the motion of objects through air. The amount of air resistance action on an object depends on the size shape and speed of the object. A object that has a larger (flatter, wider, etc) surface area falls slower. This is why parachutes slow down a sky diver to a safe speed to land. Since Air Resistance Slows objects down, is it a type of Friction?

Will air resistance have more effect on the acceleration of a falling leaf or the acceleration of a falling acorn

Terminal velocity Terminal Velocity - the velocity of a falling object when the force of air resistance is equal to the force of gravity. When a sky diver jumps out of a plane, he plummets to the ground until his parachute opens. The parachute is wide and allows more air resistance. This slows the sky diver down to a safe terminal velocity. The upward force of air balances with the downward force of gravity and he is able to land safely.

Now I’m FREEE…FREE FALLINNNNN Free Fall. What is it? An object is in Free Fall when only gravity is acting on it. The only place where a free fall can occur is a place where there is no air! Objects that float in space are actually in free fall.

Calculating Velocity of Falling objects To calculate the velocity of the falling object use the following formula  V=g x t the Triangle symbol means “change in” you will often see it when calculating motion.  So Velocity = gravity (9.8m/s) X (Time it took to fall in seconds).  Replace G with the value of gravity (9.8 m/s) and replace the t with the time given in the problem (usually in seconds).

A Diver jumps into the water from a cliff. He falls for 3 seconds before hitting the water. What was his velocity when he hit the water? V = G x T V = 9.8 m/s X 3 V =

Projectile Motion Projectile Motion is the curved path an object follows when it is thrown or “flung” into the air. Examples are frogs jumping, cannon balls, water sprinklers, baseball pitches, etc.

Projectile motion has two components – horizontal motion and vertical motion. When they are combined they form a curved path.

Projectile/ vertical motion practice or air resistance Or airplane lab