 # CHAPTER 3 ACCELERATION AND FREE FALL. ACCELERATION.

## Presentation on theme: "CHAPTER 3 ACCELERATION AND FREE FALL. ACCELERATION."— Presentation transcript:

CHAPTER 3 ACCELERATION AND FREE FALL

ACCELERATION

When velocity and acceleration are in the same direction, the speed of the object increases with time. When velocity and acceleration are in opposite directions, the speed of the object decreases with time.

ACCELERATION 4.0s v f =-10.0m/s v i =-2.0m/s

ACCELERATION 4.0s v i =-10.0m/sv f =-2.0m/s

DECELERATION VS. NEGATIVE ACCELERATION Deceleration – Reduction in speed Negative Acceleration – Acceleration vector is in the negative-x direction

INSTANTANEOUS ACCELERATION

MOTION DIAGRAMS

ONE-DIMENSIONAL MOTION WITH CONSTANT ACCELERATION Many applications of mechanics involve objects moving with constant acceleration Constant Acceleration Instantaneous acceleration = average acceleration

COMPARING MOTION GRAPHS

VELOCITY AS A FUNCTION OF TIME

REALITY CHECK

DISPLACEMENT AS A FUNCTION OF TIME The area under the line on a velocity vs. time graph is equal to the displacement of the object.

AN AUTOMOBILE MANUFACTURER CLAIMS THAT ITS SUPER- DELUXE SPORTS CAR WILL ACCELERATE UNIFORMLY FROM REST TO A SPEED OF 38.9M/S IN 8.00S.

VELOCITY AS A FUNCTION OF DISPLACEMENT

EQUATIONS FOR MOTION IN A STRAIGHT LINE UNDER CONSTANT ACCELERATION EquationInformation Given by Equation Velocity as a function of time Displacement as a function of time Velocity as a function of displacement

IN COMING TO A STOP, A CAR LEAVES SKID MARKS 92.0M LONG ON THE HIGHWAY. ASSUMING A DECELERATION OF 7.00M/S 2, ESTIMATE THE SPEED OF THE CAR JUST BEFORE BRAKING.

FREE FALL When air resistance is ignored, all objects in free fall near the Earth’s surface fall at the same constant acceleration. Galileo Dropped objects of different weights of Leaning Tower of Pisa Or did he? Inclined Planes Diluting Gravity

FREE FALL

A tennis player on serve tosses a ball straight up. While the ball is in free fall, does the acceleration A. Increase B. Decrease C. Increase then Decrease D. Decrease then Increase E. Remain Constant

FREE FALL A tennis player on serve tosses a ball straight up. While the ball is in free fall, does the acceleration A. Increase B. Decrease C. Increase then Decrease D. Decrease then Increase E. Remain Constant

FREE FALL As the tennis ball in the previous question travels through the air, its speed A. Increases B. Decreases C. Decreases then Increases D. Increases then Decreases E. Remains the Same

FREE FALL As the tennis ball in the previous question travels through the air, its speed A. Increases B. Decreases C. Decreases then Increases D. Increases then Decreases E. Remains the Same

A BASEBALL IS HIT NEARLY STRAIGHT UP INTO THE AIR WITH A SPEED OF 22M/S.