Force Facts
What is a force?
A push or pull.
What is friction?
A force that opposes motion.
What force pulls everything toward the Earth?
Gravity
When forces are equal and opposite, what are they called?
Balanced forces
What do arrows in a free body diagram represent?
Forces
What unit is used to measure force?
Newtons (N)
What type of friction keeps an object from moving?
Static friction.
What is the acceleration due to gravity on Earth?
9.8 m/s².
When an object speeds up, are the forces balanced or unbalanced?
Unbalanced
What does the length of an arrow show?
The strength of the force
What is the formula for net force when two forces act in opposite directions?
Net Force = Larger Force – Smaller Force.
What type of friction acts on an object that’s sliding?
Kinetic friction.
What tool measures weight?
A scale
If an object is not moving, what are the forces?
Balanced
What direction does friction act?
Opposite to motion
What happens to acceleration if force increases but mass stays the same?
Acceleration increases.
What are two ways to reduce friction?
Use oil or smooth the surface
What happens to your weight on the Moon?
It decreases
A car slows down — what type of force is acting?
Unbalanced
A box is pushed to the right across the floor. What four forces act on it?
Applied, friction, gravity, normal.
What two things determine how much force is needed to move an object?
Mass and acceleration.
Which type of friction is stronger — static or kinetic?
Static friction
What’s the difference between mass and weight?
Mass is matter; weight is gravity’s pull on that mass.
What causes an object to change its motion?
An unbalanced force
A falling skydiver moves at constant speed. What does that mean about the forces?
They are balanced