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Forces and Motion Practice Tests

These Grade 8 Science practice tests cover pushes and pulls, newtons, net force, balanced and unbalanced forces, gravity, friction, mass, weight, speed, acceleration, motion graphs, free-body diagrams, and introductory Newton laws.

Skills covered

  • Identifying force, net force, balanced forces, and unbalanced forces
  • Distinguishing mass from weight and contact from noncontact forces
  • Calculating and interpreting speed, acceleration, and simple F = ma relationships
  • Reading distance-time graphs and force diagrams
  • Applying inertia and Newton laws to everyday motion and safety situations

How to use these practice tests

Draw or imagine the force arrows first. Add opposite forces carefully to find net force, then decide whether the object accelerates. For numerical questions, write the relationship, substitute the known values, and check the units.

For more Grade 8 Science practice, return to the Grade 8 Science category.

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1. Test

Grade 8 Forces and Motion Practice Tests

Practice Grade 8 Science questions about forces, net force, balanced forces, friction, gravity, mass, weight, speed, acceleration, graphs, and Newton laws.

Choose the best answer for each question. Analyze force diagrams, motion data, graphs, mass, acceleration, friction, gravity, and Newton law relationships.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

What is a force?

Please select an answer first.

Correct answer: A

The correct answer is A push or pull that can change an objects motion.

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

A force is an interaction that can change motion through a push or pull.

2. QuestionMultiple choice

What is the SI unit of force?

Please select an answer first.

Correct answer: B

The correct answer is The newton.

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

Force is measured in newtons, while kilograms measure mass, meters measure length, and joules measure energy.

3. QuestionMultiple choice

What happens when forces on an object are balanced?

Please select an answer first.

Correct answer: C

The correct answer is The net force is zero and the objects motion does not change..

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

Balanced forces have equal total effects in opposite directions, so there is no acceleration.

4. QuestionMultiple choice

What happens when forces on an object are unbalanced?

Please select an answer first.

Correct answer: D

The correct answer is The net force is not zero, so the objects motion can change..

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

An unbalanced net force produces acceleration, which can change speed or direction.

5. QuestionMultiple choice

What is net force?

Please select an answer first.

Correct answer: A

The correct answer is The combined effect of all forces acting on an object.

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

Net force is the vector total of all forces and determines whether motion changes.

6. QuestionMultiple choice

How is mass different from weight?

Please select an answer first.

Correct answer: B

The correct answer is Mass is the amount of matter, while weight is the force of gravity on that mass..

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

Mass is measured in kilograms, while weight depends on gravitational force and is measured in newtons.

7. QuestionMultiple choice

What force pulls objects toward Earth?

Please select an answer first.

Correct answer: C

The correct answer is Gravity.

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

Earths gravitational force attracts objects toward its center.

8. QuestionMultiple choice

What is friction?

Please select an answer first.

Correct answer: D

The correct answer is A force that opposes motion between surfaces in contact.

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

Friction acts against relative motion between surfaces and can slow an object.

9. QuestionMultiple choice

Which is a noncontact force?

Please select an answer first.

Correct answer: A

The correct answer is Gravity acting on a falling object.

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

Gravity acts at a distance, while the other examples require physical contact.

10. QuestionMultiple choice

Two students push a box with 40 N east and 40 N west. What is the net force?

Please select an answer first.

Correct answer: B

The correct answer is 0 N.

  1. Identify the motion information: Find the direction, distance, time, speed, acceleration, mass, or force described in the situation or data.
  2. Compare forces: Determine whether forces are balanced, calculate the net force when possible, and connect the result to motion.
  3. Apply the model: Use Newton law relationships, diagrams, graphs, or observations to explain the change in motion.

Equal opposite forces cancel, so the net force is zero.

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