Download Forces change motion

DO NOW
Hand in “Acceleration and Slope
Lab” in your class bin.
Open notebooks to take short
notes on forces and motion. Title
notes “Forces change motion”
Forces change motion
Chapter 2.1
Forces
Force: A push or pull; changes the motion
of an object
Types of Forces
 Contact Force: one object
pushes or pulls another
object by touching it
 Gravity: force of attraction
between two masses (Earth’s
gravity)
 Friction: resists motion
between two surfaces that
are pressed together
Balanced and Unbalanced Forces
 Force is a vector: has both size and direction
 Net Force: the overall force acting on an object when all the
forces are combined
 Balanced Forces: the net force is zero
 Unbalanced Forces: one force is greater than the other(s)
Forces on Moving Objects
 As long as forces are balanced, an object can move at
a constant velocity.
 Ex: riding your bike at a constant speed. If you stop
pedaling, eventually your bike will come to a stop
 An unbalanced force is needed to change an object’s
motion.