Newton's First Law - AP Physics 1

If two people push a box equally from opposite sides, what is the net force?

Zero. Equal and opposite forces result in no net force.
How does mass affect an object's inertia?

Greater mass, greater inertia. Mass directly determines how much an object resists motion changes.
Describe motion when net force on an object is zero.

Constant velocity or at rest. Newton's First Law describes motion under equilibrium conditions.
What is the effect of friction on a moving object?

It opposes motion, creating a net force. Creates unbalanced force that causes deceleration over time.
What is Newton's First Law of Motion?

An object remains at rest or in uniform motion unless acted on by a net external force. Also known as the law of inertia, fundamental principle of mechanics.
What is the unit of force in the International System of Units (SI)?

Newton (N). Standard unit for measuring force in physics calculations.
Identify the correct outcome: An unbalanced force causes uniform motion.

Incorrect, causes acceleration. Unbalanced forces create acceleration, not uniform motion.
State the condition for an object to be in equilibrium.

Net external force is zero. When all forces balance out, no acceleration occurs.
What is the result of balanced forces acting on an object?

No change in motion. Equal and opposite forces cancel out, maintaining current motion state.
What happens to an object if all forces cancel each other?

No change in motion. Equilibrium condition maintains current state of motion.
In a tug-of-war, if both sides pull equally, what is the net force?

Zero. Equal forces in opposite directions cancel completely.
Choose the correct statement: Objects in space can move without force.

True, if no net force acts. Space has no friction, so objects maintain motion indefinitely.
What is the relationship between inertia and mass?

Directly proportional. More massive objects have greater resistance to motion changes.
If an object experiences zero acceleration, what can be said about the net force?

Net force is zero. Zero acceleration implies forces are balanced per Newton's laws.
Which law describes the relationship between force, mass, and acceleration?

Newton's Second Law. Expressed mathematically as $F = ma$ for net force calculations.
Define equilibrium in terms of forces.

Sum of forces equals zero. Mathematical condition for Newton's First Law to apply.
For an object moving at constant speed in a circle, is there a net force?

Yes, centripetal force. Circular motion requires constant inward force for direction change.
Explain using Newton's First Law: A spacecraft coasting in space.

No net force, constant velocity. No external forces act, so spacecraft maintains constant velocity.
What is the effect of removing a net force from a moving object?

Continues in uniform motion. Inertia maintains the existing motion when forces are removed.
What happens to an object's velocity if a net force suddenly stops acting?

Remains constant. Inertia maintains velocity when net force becomes zero.
What happens to an object in motion when no net force acts on it?

It continues in uniform motion. Objects maintain constant velocity when no net force acts on them.
What is required to change an object's state of motion?

Net external force. Only unbalanced forces can alter an object's motion state.
What term describes forces that do not change an object's motion?

Balanced forces. Forces that cancel each other out completely.
If an object is moving at constant velocity, what is the net force?

Zero. Constant velocity indicates all forces are perfectly balanced.
In the absence of external forces, what remains constant for a moving object?

Velocity. No external forces means no change in motion state.
What will happen to a stationary object if a net force is applied?

It will accelerate. Net force causes change from rest to motion state.
Name the tendency of an object to resist changes in motion.

Inertia. Fundamental property that opposes any change in motion.
Which force acts against motion and affects velocity?

Friction. Opposes motion and creates net force when present.
State the principle that explains why passengers lurch forward in a stopping car.

Inertia. Objects continue moving forward when vehicle suddenly stops.
Identify the force required to maintain constant velocity in the absence of friction.

No force is required. Objects naturally maintain constant velocity without external forces.
Predict the motion: A car moving at constant speed on a straight road.

Net force is zero. Constant speed indicates balanced forces acting on the vehicle.
What property of an object quantifies its inertia?

Mass. Greater mass means greater resistance to changes in motion.
Identify the force acting on a stationary object on a frictionless surface.

No net force. No friction or other forces to change motion state.
What quantity is needed to overcome inertia?

Force. External force required to overcome natural resistance to change.
Identify the term for the resistance to change in motion.

Inertia. The property that makes objects resist changes to their motion state.
State the law that explains why a book remains on a table.

Newton's First Law. Gravity and normal force balance, creating equilibrium state.
What type of force must act for a change in motion to occur?

Net external force. Only unbalanced forces can cause acceleration or deceleration.
Find and correct the error: A net force can be zero if forces are unbalanced.

Correct: Forces must be balanced. Zero net force requires balanced forces, not unbalanced ones.
Define net force.

The vector sum of all forces acting on an object. Determines whether an object will accelerate or remain in equilibrium.
What happens to an object at rest when no net force acts on it?

It remains at rest. Newton's First Law states objects at rest stay at rest without net force.

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