Grade 8 Science Worksheet: Forces (Mixed Practice)

Forces Mixed Practice

Grade 8 Science Forces Mixed Practice Advanced 40 Questions 22 Views

Classroom Worksheet

Grade 8 Science Worksheet: Forces (Mixed Practice)

Forces Mixed Practice

Name____________________________

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Score______ / 40

Grade: Grade 8

Subject: Science

Topic: Forces

Time: 20 Minutes

Difficulty: Advanced

Questions: 40

Instructions:
Read each question carefully and answer in complete sentences when needed. Show your work for calculation questions. Questions become more challenging as you move through the worksheet.

Skills Practiced:

Forces
Science
Critical Thinking
Problem Solving

1Question

What is a force?

2Question

Name one unit used to measure force.

3Question

Is force a scalar or a vector quantity?

4Question

What force pulls objects toward Earth?

5Question

What type of force slows down moving objects when two surfaces rub together?

6Question

Give one example of a contact force.

7Question

Give one example of a non-contact force.

8Question

What is the net force if two equal and opposite forces act on an object?

9Question

What happens to an object's motion if the net force acting on it is not zero?

10Question

A book rests on a table. What force from the table acts upward on the book?

11Question

A force of 12 N acts to the right and a force of 5 N acts to the left. What is the net force and direction?

12Question

A cart is pulled with 15 N to the east and pushed with 15 N to the west. What is the net force?

13Question

A student pushes a box with 20 N to the left. What is the direction of the force?

14Question

What is acceleration?

15Question

According to Newton's second law, what happens to acceleration when force increases and mass stays the same?

16Question

According to Newton's second law, what happens to acceleration when mass increases and force stays the same?

17Question

If a 2 kg object experiences a force of 10 N, what is its acceleration?

18Question

If a 4 kg object accelerates at 3 m/s², what net force acts on it?

19Question

A 6 kg object is acted on by a net force of 18 N. What is its acceleration?

20Question

Why does a heavier object usually need more force to accelerate by the same amount as a lighter object?

21Question

What is inertia?

22Question

Which has more inertia: a soccer ball or a bowling ball?

23Question

A moving bike slows down when the rider stops pedaling. What force is mainly causing this change?

24Question

What is air resistance?

25Question

Why does a parachute help a skydiver fall more slowly?

26Question

What is the difference between balanced and unbalanced forces?

27Question

A tug-of-war team pulls with 400 N to the left, and the other team pulls with 450 N to the right. What is the net force?

28Question

A 10 kg object has a net force of 0 N acting on it. What can you say about its motion?

29Question

A car is moving at a constant speed in a straight line. What can you conclude about the net force?

30Question

What force acts between two magnets when they push apart?

31Question

Why do shoes with deep tread patterns often provide better grip on wet ground?

32Question

A student uses 30 N to pull a sled east. Friction acts with 12 N west. What is the net force?

33Question

A 5 kg object has a net force of 25 N. If the force is doubled while the mass stays the same, what is the new acceleration?

34Question

A 3 kg cart accelerates at 4 m/s². If the mass becomes 6 kg and the net force stays the same, what is the new acceleration?

35Question

Why is it easier to stop a rolling soccer ball than a rolling truck moving at the same speed?

36Question

Describe how Newton's third law applies when a swimmer pushes water backward.

37Question

A rocket moves upward because gases move downward. Which Newton's law explains this?

38Question

A 8 kg object is moving and a net force of 16 N acts on it. What is its acceleration, and in which direction will it accelerate if the force is to the right?

39Question

A box experiences 25 N to the right and 10 N to the left. The box has a mass of 5 kg. Find the net force and acceleration.

40Question

Explain why seat belts are important in a sudden stop using the idea of inertia.

Answer Key

#	Answer
1	A force is a push or a pull that can change an object's motion or shape.
2	Newton (N).
3	Force is a vector quantity because it has both size and direction.
4	Gravity.
5	Friction.
6	Examples include friction, tension, normal force, or air resistance.
7	Examples include gravity, magnetic force, or electric force.
8	The net force is 0 N.
9	Its motion changes; it may speed up, slow down, or change direction.
10	The normal force.
11	7 N to the right.
12	0 N.
13	To the left.
14	Acceleration is the rate at which an object's velocity changes.
15	Acceleration increases.
16	Acceleration decreases.
17	5 m/s². (a = F/m = 10/2)
18	12 N. (F = ma = 4 × 3)
19	3 m/s². (a = F/m = 18/6)
20	Because a heavier object has more mass and resists changes in motion more.
21	Inertia is the tendency of an object to resist changes in its motion.
22	The bowling ball.
23	Friction and air resistance.
24	Air resistance is a force that opposes motion through air.
25	It increases air resistance, which reduces the skydiver's speed.
26	Balanced forces are equal and opposite, so the net force is 0 N; unbalanced forces do not cancel, so the net force is not 0 N.
27	50 N to the right.
28	It will stay at rest or keep moving at a constant velocity.
29	The net force is 0 N.
30	Magnetic repulsion.
31	They increase friction between the shoe and the ground.
32	18 N east.
33	10 m/s². The original acceleration is 5 m/s², and doubling the force doubles the acceleration.
34	2 m/s². The force is 12 N, and 12/6 = 2.
35	The truck has more mass and more inertia, so it is harder to change its motion.
36	The swimmer pushes water backward, and the water pushes the swimmer forward with an equal and opposite force.
37	Newton's third law.
38	2 m/s² to the right.
39	Net force = 15 N to the right; acceleration = 3 m/s² to the right.
40	Seat belts help keep passengers moving with the car when it stops suddenly, because inertia makes their bodies continue moving forward.