Newton's Laws Quiz
Questions: 16 · 10 minutes
1. Two horizontal forces act on a 4 kg box: 30 N to the right and 10 N to the left. What is the box’s acceleration?
10 m/s² to the right
5 m/s² to the left
5 m/s² to the right
0 m/s² because both forces are horizontal
2. Which statement best summarizes Newton’s first law?
An object can keep moving only while a forward force continuously acts on it.
An object maintains its state of rest or constant-velocity motion unless acted on by a net external force.
Every moving object naturally accelerates until resistance balances its motion.
The acceleration of an object always points in the direction it is moving.
3. A small car collides head-on with a much heavier truck. During the collision, how do the forces they exert on each other compare?
They are equal in magnitude and opposite in direction.
The truck exerts a larger force because it has greater mass.
The car exerts a larger force because it undergoes greater damage.
The forces are equal only if neither vehicle changes speed.
4. A bus moving forward brakes sharply, and a standing passenger appears to lurch toward the front. What is the best explanation?
The passenger’s mass briefly increases, producing forward motion.
Braking creates a new forward force that pulls the passenger toward the front.
The passenger’s body tends to continue at its previous velocity while the bus slows beneath them.
The bus exerts no forces on the passenger while braking.
5. A 4 kg cart experiences a net horizontal force of 12 N. What is its acceleration?
8 m/s²
0.33 m/s²
3 m/s²
48 m/s²
6. Which two forces form a Newton’s third-law pair when an apple falls toward Earth?
Earth’s pull on the apple and air resistance on the apple
Earth’s gravitational pull on the apple and the apple’s gravitational pull on Earth
The apple’s weight and its downward acceleration
Earth’s pull on the apple and the apple’s momentum
7. A rocket accelerates upward by expelling hot gas downward. Which explanation best applies Newton’s third law?
The rocket’s upward force must always be greater than the downward force on the gas.
The rocket pushes gas downward, and the gas pushes the rocket upward with an equal-magnitude force.
The gas pushes only on the surrounding air, which then lifts the rocket.
The exhaust reduces gravity’s pull on the rocket.
8. What must be true when all the forces acting on an object add to a net force of zero?
The object must be at rest.
The object has zero acceleration, although it may be at rest or moving at constant velocity.
The object has no forces acting on it.
The object must be moving in a straight line.
9. A person stands on a scale inside an elevator that is accelerating upward. How does the scale’s upward normal force compare with the person’s weight?
It is greater than the person’s weight, producing a net upward force.
It equals the person’s weight because action and reaction forces are equal.
It is zero because the elevator supplies the acceleration.
It is smaller than the person’s weight because the elevator is moving upward.
10. When a car stops suddenly, an unrestrained passenger tends to continue moving forward. Which law most directly explains this?
Newton’s second law, because the passenger’s mass increases
Newton’s third law, because the car and passenger exert equal forces
The law of gravitation, because gravity pulls the passenger forward
Newton’s first law, because the passenger’s body tends to maintain its motion
11. A swimmer pushes water backward with their hands. Which statement correctly describes the relevant action–reaction pair?
The swimmer pushes the water backward, while water resistance pushes the water forward.
The swimmer’s weight pushes downward, while the water pushes the swimmer forward.
The swimmer pushes the water backward, and the water pushes the swimmer forward with an equal-magnitude force.
The swimmer pushes the water backward with more force than the water exerts on the swimmer.
12. A hockey puck is given a brief push on an ideal horizontal surface with no friction. What will it do after contact with the stick ends?
Slow gradually because motion requires a continuing force
Accelerate continuously because it retains the force of the push
Stop immediately because the applied force has ended
Continue at constant velocity in a straight line
13. A spacecraft far from significant gravitational influences travels in a straight line at constant speed with its engines off. What is the net force on it?
A forward force equal to its momentum
A backward force that will eventually stop it
A force that increases as it travels farther
Zero net force
14. A constant net force acts on an object whose mass does not change. What happens to the object?
It moves at constant velocity because the force is constant.
Its mass gradually decreases as its speed increases.
It accelerates in the direction opposite the net force.
It accelerates in the direction of the net force.
15. A book rests motionless on a level table. Which pair of forces acting on the book balances vertically?
The downward gravitational force on the book and the table’s upward normal force on the book
The table’s weight and the upward force of the floor
The book’s weight and Earth’s reaction force on the table
The book’s weight and the force the book exerts on the table
16. The same net force is applied separately to two objects, but the second object has twice the mass of the first. How does the second object’s acceleration compare?
It is half as large.
It is twice as large.
It is four times as large.
It is the same because the net force is unchanged.