Types of Forces
What force pulls objects toward Earth and always acts downward?
Gravity
What is Newton’s Third Law of Motion?
For every action, there is an equal and opposite reaction.
What effect does adding oil to a door hinge have on friction?
Decreasing Friction
Which force pulls all objects downward with the same acceleration if there’s no air?
Gravity
What is it called when forces are equal in strength and opposite in direction?
Balanced Forces
What force opposes motion between two surfaces that are touching?
Friction
If you push a wall, what does the wall do?
It pushes back on you with equal force in the opposite direction.
How does decreasing friction affect the speed of objects?
Objects move faster.
Which object falls slower because air resistance affects it more: a feather or a marble?
A feather
What is the net force when forces are balanced?
0 Newtons
What is the force called that a surface pushes up on an object resting on it, at a right angle?
Normal Force
When a stick hits a piñata, what force does the piñata apply back on the stick?
Equal and opposite force.
What type of surface or object increases friction and slows down motion?
Rough surfaces or parachutes
What would happen to a feather and a marble if they fell in a vacuum?
They would fall at the same rate.
What happens to the motion of an object when unbalanced forces act on it?
It changes (speeds up, slows down, or changes direction).
What kind of force is applied by a person or another object, like pushing a box?
Applied Force
When you stand on the ground, what force does the ground apply to you?
The normal force pushing up on you.
Why does water on a slide make you go faster?
It decreases friction.
Does air resistance affect heavier objects more or lighter objects more?
Lighter Objects
Is the box on a table with gravity pulling down 50 N and normal force pushing up 50 N an example of balanced or unbalanced forces?
Balanced Forces
What is the name of the friction force that acts against objects moving through air?
Air Resistance
Newton’s Third Law states forces always come in what?
Pairs
What happens to a skydiver when a parachute opens?
Friction increases, slowing the skydiver down.
Why does a feather fall slower than a marble on Earth?
Because air resistance affects the feather more.
What is the net force if Team A pulls 500 N right and Team B pulls 400 N left?
100 N to the right