Acceleration

Acceleration: 1. the rate of change of velocity. 2. can occur through a change in speed or direction.

Two types of acceleration: Positive Acceleration- -velocity and acceleration are in the same direction. Velocity Acceleration

Negative Acceleration -velocity & acceleration are in opposite directions. -also called deceleration Velocity Acceleration

a = vf – vi t Calculating Acceleration: Velocity final – Velocity initial time Acceleration = or a = vf – vi t

Units of Acceleration ___meters____ second x second or m/s2

POSITIVE OR NEGATIVE? If your answer is a positive number, this means the object is accelerating. (positive acceleration) -If your answer is a negative decelerating. (negative acceleration)

Variations of the Acceleration Formula Solving for time: t = vf – vi a Solving for final velocity: vf = at + vi Solving for initial velocity: vi = vf at

1. A driver floors the gas pedal on her 1. A driver floors the gas pedal on her Ferrari and reaches 35 m/s in about 4.3 seconds. Assuming the car started at rest, how fast did it accelerate? a = vf = vi = t =

A bicyclist hits a moose while traveling at 19 m/s. It took the bicyclist .25 seconds to stop. Luckily the moose was fine, but the bicyclist had to be transported to local. At what what rate did the bicyclist decelerate? a = vf = vi = t =

3. A water balloon dropped from a window accelerates at a speed of 9.8 m/s2 reaching a final velocity of 15 m/s before hitting a person. How much time does it take the balloon to reach this rate of acceleration? a = Vf= Vi= t=

4. A swimmer speeds up from 1.6 m/s to 2.2 m/s during the last 20 seconds of his workout. What was his acceleration during this interval? a = vf = vi = t =

5. A rocket is launched from the white sands test site. It has a mass of 800 kg and can reach a top velocity of 700 m/s. If it takes 3.1 seconds to reach this velocity, what is its acceleration? a= vf= vi= t=