Newton’s First Law
An object keeps moving at the same speed and direction unless a force acts on it. What law is this?
Newton’s First Law
If force increases and mass stays the same, what happens to acceleration?
It increases
When you push on a wall, what does the wall do?
Pushes back with equal force.
If forces are balanced, the net force equals…?
Zero
If an object is slowing down while moving right, friction acts in which direction?
Left
A hockey puck slides smoothly across ice until friction slows it. What type of force changed its motion?
An unbalanced force
A 4 kg object accelerates at 3 m/s². What is the net force?
12 N
Why does a swimmer move forward when pushing water backward?
Water pushes forward equally.
A car moves at constant speed on a straight road. Is it in static or dynamic equilibrium?
Dynamic equilibrium.
If an object speeds up while moving left, the net force must be pointing…?
Left
If an object is moving and the net force becomes zero, what happens to its motion?
It keeps moving at the same velocity
What happens to acceleration if the same force is applied to a larger mass?
Acceleration decreases
A hammer hits a nail. Why does the nail accelerate more than the hammer?
Forces are equal, but the nail has less mass.
A box has 25 N right and 25 N left. What is the net force?
0 N
A ball is tossed upward. While moving up, what two forces act on it?
Gravity and air resistance.
A book sitting on a table stays still until someone pushes it. What property keeps it at rest?
Inertia
A net force of 18 N acts on a 6 kg object. What is the acceleration?
3 m/s²
Why don’t action–reaction forces cancel each other out?
They act on different objects
A runner speeds up. Are the forces balanced or unbalanced?
Unbalanced
A block is sliding left with no acceleration. What does this mean about the forces?
They are balanced
A cart on a frictionless track is pushed once and then glides without slowing. Why does it not stop?
No unbalanced force acts to slow it.
A student pushes two carts with the same force, but one cart has twice the mass. How do their accelerations compare?
The heavier cart accelerates half as much.
A rocket launches upward because gases are pushed downward. Which force pair is this?
Exhaust pushes down; rocket is pushed up equally.
A crate is pushed but does not move. What force must be matching the push?
Static friction.
A 10 N upward force and a 12 N downward force act on an object. What is the net force and direction?
2 N downward