Force and Motion Quiz 8th Grade
Questions: 16 · 10 minutes
1. A distance-time graph has a horizontal segment from 10 seconds to 15 seconds. What happened during that interval?
The object moved at a constant nonzero speed.
The object accelerated at a constant rate.
The object returned toward its starting point.
The object remained at the same location.
2. A hockey puck moves in a straight line at constant velocity. What can be concluded about the forces acting on it?
No forces of any kind are acting on it.
A forward force is greater than every opposing force.
Its weight must be equal to zero.
The forces are balanced, so the net force is zero.
3. What distinguishes velocity from speed?
Velocity measures distance, while speed measures time.
Velocity includes both how fast an object moves and its direction.
Velocity applies only to accelerating objects.
Velocity is always greater than speed.
4. A runner travels 150 meters in 30 seconds at a steady pace. What is the runner’s average speed?
0.2 m/s
5 m/s
4 m/s
180 m/s
5. An astronaut carries the same tool from Earth to the Moon. How do the tool’s mass and weight change?
Its mass and weight both decrease.
Its mass and weight both stay the same.
Its mass decreases, but its weight stays the same.
Its mass stays the same, but its weight decreases.
6. Four forces act on an object: 10 N upward, 10 N downward, 6 N right, and 2 N left. What is the net force?
20 N upward
4 N to the right
8 N to the right
4 N downward
7. Two horizontal forces act on a box: 18 N to the right and 11 N to the left. What is the net force?
29 N to the right
29 N to the left
7 N to the left
7 N to the right
8. A book slides across a table and eventually stops even though no one touches it again. What force is mainly responsible?
Gravity acting in the direction of the book’s motion
The book’s inertia pushing opposite its motion
Friction acting opposite the book’s motion
An upward force from the table slowing the book horizontally
9. A person on a skateboard pushes against a wall and rolls backward. Which statement correctly describes the action-reaction pair?
The person’s push and the wall’s push cancel because both act on the wall.
The person pushes the wall first, and the wall produces a smaller force later.
The person pushes the wall, and the wall pushes the person with an equal force in the opposite direction.
The wall pushes only if the skateboard is already moving.
10. A student walks 3 meters east and then 3 meters west, ending at the starting point. What are the total distance and displacement?
Distance is 0 m, and displacement is 6 m east.
Distance is 6 m, and displacement is 0 m.
Distance is 6 m, and displacement is 6 m west.
Distance is 3 m, and displacement is 3 m west.
11. A bus suddenly moves forward from rest, and a standing passenger appears to sway backward. Which principle best explains this?
The passenger gains more mass when the bus starts moving.
Gravity briefly pulls the passenger toward the rear of the bus.
Inertia tends to keep the passenger’s body at rest while the bus accelerates forward.
The forward motion of the bus removes friction from the passenger’s feet.
12. A heavy ball and a light ball are dropped together in a vacuum, where there is no air resistance. What happens?
The light ball accelerates faster because it has less inertia.
The heavy ball accelerates faster because gravity pulls harder on it.
They have the same downward acceleration and land together.
Neither ball accelerates because a vacuum has no gravity.
13. Why does a seat belt help protect a passenger when a moving car stops suddenly?
It provides a force that slows the passenger with the car instead of letting inertia carry the passenger forward.
It prevents gravity from acting on the passenger.
It makes the passenger continue forward at the car’s original speed.
It removes the passenger’s mass during the stop.
14. The same unbalanced force is applied separately to two carts. Cart A has less mass than Cart B. How will their accelerations compare?
Cart A will accelerate more because the same force acts on less mass.
Cart B will accelerate more because it has more mass.
Both carts will accelerate equally because the forces are equal.
Neither cart will accelerate unless its mass changes.
15. A car travels around a circular track at a constant speed. Why is the car still accelerating?
Its direction, and therefore its velocity, is continually changing.
Its mass changes as it travels around the track.
Constant speed always means the forward force is increasing.
Gravity increases the car’s speed on every part of the track.
16. A bicycle’s velocity increases from 4 m/s to 16 m/s in 6 seconds. What is its average acceleration?
2 m/s²
1.3 m/s²
0.5 m/s²
12 m/s²