Forces Quiz
Questions: 16 · 10 minutes
1. Which statement best expresses Newton’s first law of motion?
An object maintains its state of rest or constant-velocity motion unless acted on by a net external force
Every force produces an equal acceleration regardless of mass
Forces always occur in pairs that cancel on the same object
An object can keep moving only while a forward force acts on it
2. An elevator is moving upward at a constant speed. What is the net force on the elevator?
Upward, because the elevator is moving upward
Zero, because the elevator’s velocity is constant
Downward, because gravity continues to act
Equal to its weight and directed upward
3. A ball moves at constant speed in a horizontal circle on a string. In which direction does the net force on the ball point?
Opposite the ball’s instantaneous direction of travel
Away from the center of the circle
Along the ball’s instantaneous direction of travel
Toward the center of the circle
4. A book rests motionless on a level table. Which force directly balances the book’s weight?
Static friction from the table
Air resistance acting upward
The book’s gravitational pull on Earth
The normal force from the table
5. A swimmer pushes water backward with their hands. According to Newton’s third law, what paired force helps move the swimmer?
The swimmer’s weight pulls the water upward
The water pushes the swimmer forward
The water’s resistance stops acting once the hands move
The water pushes the swimmer backward with a smaller force
6. A box is sliding to the right across a rough, level floor after the pushing force has been removed. Which horizontal force mainly causes it to slow down?
Its weight acting to the left
The normal force acting to the left
Kinetic friction acting to the left
Static friction acting to the right
7. A skydiver falls at constant terminal velocity. What does this tell you about the forces on the skydiver?
Gravity is no longer acting
The downward force remains greater because the skydiver is moving downward
Air resistance is greater than the skydiver’s weight
Air resistance balances the skydiver’s weight, so the net force is zero
8. A passenger wearing a seat belt is in a car that stops suddenly. What is the seat belt’s main role during the stop?
It removes the passenger’s inertia
It exerts a force that slows the passenger with the car
It cancels the passenger’s weight
It creates a forward force that maintains the passenger’s speed
9. A net force accelerates a 3 kg object at 4 m/s². What is the magnitude of the net force?
0.75 N
7 N
12 N
24 N
10. A car experiences a 1,200 N driving force forward and 800 N of combined resistance backward. What is the net force on the car?
400 N forward
400 N backward
800 N forward
2,000 N forward
11. Which SI unit is used to measure force?
Newton
Joule
Watt
Pascal
12. An astronaut carries the same tool from Earth to the Moon. Which statement correctly compares the tool’s mass and weight?
Its mass stays the same, but its weight decreases
Its mass decreases, but its weight stays the same
Both its mass and weight stay the same
Both its mass and weight decrease by the same proportion
13. A spring obeys Hooke’s law and remains within its elastic limit. If its extension is doubled, what happens to the force exerted by the spring?
It stays the same
It doubles
It increases by a factor of four
It is reduced by half
14. The same net force is applied separately to two carts, but one cart has less mass. How does the lower-mass cart respond?
It has less acceleration because it has less inertia to overcome
It has the same acceleration because the force is the same
It moves at constant speed because its mass is smaller
It has greater acceleration because acceleration equals net force divided by mass
15. Two objects attract each other gravitationally. If the distance between their centers doubles while their masses remain unchanged, what happens to the gravitational force?
It becomes half as large
It doubles
It becomes one-quarter as large
It becomes four times as large
16. In physics, what is a force?
The energy an object possesses because it is moving
The amount of matter contained in an object
A push or pull that can change an object’s motion or shape
The distance an object travels in a given time