 # ACCELERATION Motion is change of position

## Presentation on theme: "ACCELERATION Motion is change of position"— Presentation transcript:

ACCELERATION Motion is change of position
Motion is described by velocity: How fast? Which way? Changing motion means: Speeding up, Slowing down, Changing direction (turning)

ACCELERATION A car is accelerating whenever there is a change in velocity Acceleration also applies to changes in direction. It is important to distinguish between speed and velocity. Acceleration is defined as the rate of change in velocity, rather than speed

ACCELERATION Acceleration is the rate at which velocity changes:
Acceleration is how fast how fast changes or how fast the direction changes

Falling upward: constant acceleration
Now consider a ball thrown straight up at 30 m/s: What happens on the way up? How fast is the ball moving 1 s, 2 s, 3 s later? Where is the ball when v = 0? How long does the ball take to reach the highest point? How fast is the ball moving 4 s later? How long does the ball take to reach the person? How fast is the ball moving when it reaches the person?

Ball Toss Experiment Ball is in your hands Ball is in your hands

Ball Toss Experiment Ball is in the air Ball is in the air
Ball is in your hands Ball is in the air Ball is in your hands

Motion with Constant Acceleration
- 4.8 X 2 = 9.6 equal equal

Motion with Constant Acceleration
General equations: y = ½ at2 + vot v = at + vo a is constant ( a number)

Free Fall: Constant Acceleration
The acceleration of an object in free fall is about 10 meters per second every second Or 10 m/s/s The rock is falling faster and faster: Each second its velocity increases by 10 m/s Fill out the table: Time, seconds Velocity, m/s 1 2 3 4 t Time, seconds Velocity, m/s 1 10 2 20 3 30 4 40 t 10t Graph these values: make a velocity-time graph

Motion with Constant Acceleration
Velocity-Time Graph On a velocity-versus-time graph, acceleration = slope

Free Fall: Constant Acceleration
The acceleration of an object in free fall is about 10 meters per second every second Or 10 m/s/s The rock is falling faster and faster: Each second its velocity increases by 10 m/s Time, seconds Velocity, m/s 1 10 2 20 3 30 4 40 t 10t

Motion with Constant Acceleration
Position-Time Graph y = ½ at2

Position, Velocity, and Acceleration
Motion Graphs Constant Acceleration Graphs Race Cars