September 22, 2016
2.3 Acceleration
Acceleration - the rate of change of velocity
• When an object's velocity changes it is accelerating
• Must have a direction
• Speed-time graphs & acceleration
Glenco Physical Science 2012
• Calculating Acceleration
a=
vf - vi
t 2
• Acceleration unit is m/s
• Remember a negative number = opposite direction
A skateboarder has an initial velocity of 4 m/s west
and comes to a stop in 3 s. What is the
skateboarder's acceleration?
September 22, 2016
Motion in Two Dimensions
• Anything that changes direction is accelerating
• Just as with displacement and velocity, accelerations
that are not in the same or opposite directions cannot
be directly combined
• Circular Motion
> On a carousel the horse moves in a circular path.
Speed remains constant but it is accelerating
toward the center of the circle
> Centripetal acceleration - acceleration toward the
center of a curved or circular path
Glenco Physical Science 2012
September 22, 2016
Projectile motion - objects thrown straight will also travel
downward
Horizontal and vertical motion
Glenco Physical Science 2012
September 22, 2016
Throwing and dropping
A thrown ball and a dropped ball will hit the ground at
the same time
Both must travel the same vertical distance in the same
amount of time
Glenco Physical Science 2012
September 22, 2016
Steve and Sally travel to the store in 350s. If
the store is 500m away, what is their speed?
Bob has a mass of 65 kg and is traveling with a
velocity of 3.5 m/s. What is Bob's momentum?
September 22, 2016
Homework:
Read p 56 - 60
P 58 # 22-24
P 60 # 27, 29,30