Download Force and Motion Force: a push or a pull that causes a change in

Force and Motion
Force: a push or a pull that causes a change in movement or shape
Example: Pushing a baby stroller
Pulling on a rope
Motion: the change in position of an object as compared to a fixed point
- Distance: length of the actual path traveled by an object
- Speed: distance traveled by an object in a given amount of time
- Velocity: object’s speed in a given direction
 Velocity (v) = distance (d) / time (t)
Example:
Speed = 80 miles per hour
Velocity = 80 miles per hour NORTH
Acceleration: a change in velocity over time.
- Acceleration of an object in a free fall on the Earth:
 = 9.8 m/s2
3 Forces that affect Motion
1) Friction: A force that resists the motion of 2 surfaces/objects touching each
other; slows down or prevents motion.
Example: car tires on a road surface
2) Gravity: Force of attraction between 2 or more objects;
Weight is a measure of the force of gravity on an object.
 Rate of acceleration (free fall) is constant because of gravity’s pull.
3) Upward Force: a force used to support something.
Example: If a book is resting on a table, the table is exerting an upward
force on the book.
Example with all three Forces:
r = upward force of ramp
g = gravity’s pull down
f = friction between car and ramp
Other Forces
Net Force: the sum of all the forces acting on an object.
Balanced Forces: when the total of all forces equal zero; no change in motion.
Net Force = ZERO
Unbalanced Forces: when the total of all forces DOES NOT equal zero; produce a
change in motion
Net Force = greater than zero
 Forces must be unbalanced to change an object’s motion.