Download Speed, Velocity, Acceleration, and Force

Study Guide for Topic #19:
Speed, Velocity,
Acceleration, and Force
What is the difference between speed and
velocity?
• The rate at which an object moves is
its speed.
• Velocity is speed in a particular
direction.
How do you calculate average speed?
average speed=
total distance
total time
How do you add two different velocities?
If the objects are moving in the same
direction, all you have to do is add them.
The final velocity will be in that same
direction.
If the objects are moving in opposite
directions:
1. Take the difference.
2. The final velocity will be in the
direction of the larger velocity.
What is acceleration?
Acceleration is any change in velocity.
• If an object’s speed changes, that is
acceleration.
• If an object’s direction changes, that
is acceleration – even at the same
speed!
How do you calculate acceleration?
acceleration=
final velocity − initial velocity
time it takes to change velocity
What is a force?
• A force is just a push or a pull.
• A force always has a size and a
direction.
• The metric unit for force is the
Newton (N).
How do forces add up?
Forces add in exactly the same way as we
used for velocity!
If the forces are in the same direction, all
you have to do is add them. The net force
will be in that same direction.
If the forces are pointing in opposite
directions:
1. Take the difference.
2. The net force will be in the direction
of the larger force.
What is the difference between a balanced
and an unbalanced force?
When the forces applied to an object
produce a net force of zero, the forces are
balanced. In this case:
• There will be no acceleration.
• Therefore, velocity will not change.
• Therefore, neither speed nor
direction will change!
• In other words, the object will “keep
on doing what it was doing.”
When the net force on an object is NOT
zero, the forces are unbalanced. In this
case:
• There will be acceleration.
• Velocity will change.
• Speed and/or direction will change!
© 2016 Bruce H. McCosar