Forces and Motion Worksheet - KS3 - Beginner

Forces and Motion worksheet for KS3 (Key Stage 3 / Year 7-9 (Ages 11-14)). Beginner level science practice, aligned to the UK National Curriculum. Print-ready with answer key included.

Science•Key Stage 3 / Year 7-9 (Ages 11-14)•Forces and Motionbeginner

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Forces in Action: Motion, Friction and Pressure

Key Stage 3 Science | Years 7–9 | Beginner

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Instructions: Work through the activities in order. Use the formulae and reminders provided, show your working for calculations, and include units where appropriate. Force is measured in newtons (N), distance in metres (m), time in seconds (s), speed in metres per second (m/s), and pressure in pascals (Pa).

Balanced or Unbalanced?

Compare the forces acting in each situation. Forces in opposite directions balance when they are equal; the resultant force is then zero. If they are unequal, subtract the smaller force from the larger force and state the direction of the resultant force.

1. A book rests on a desk. The desk pushes upwards with 5 N and gravity pulls downwards with 5 N. Are the forces balanced or unbalanced?

2. A trolley is pushed forwards with 12 N while friction acts backwards with 7 N. Find the resultant force and its direction.

3. Two people pull a rope in opposite directions with forces of 18 N and 18 N. Find the resultant force.

4. A ball is pushed to the right with 9 N and to the left with 4 N. Find the resultant force and its direction.

Calculate Speed

Use speed = distance ÷ time. Divide the distance travelled by the time taken, then write the answer in metres per second (m/s). The example shows the method: 20 m ÷ 4 s = 5 m/s.

1. A runner travels 60 m in 10 s. Calculate the runner’s speed.

2. A cyclist travels 150 m in 30 s. Calculate the cyclist’s speed.

3. A toy car travels 24 m in 6 s. Calculate its speed.

4. A swimmer travels 50 m in 25 s. Calculate the swimmer’s speed.

Speed Data Check

Read the recorded distances and times in the table. Calculate each speed using speed = distance ÷ time. Then use your calculated speeds to answer the comparison question.

Test	Distance (m)	Time (s)
A	40	8
B	54	9
C	36	12

1. Calculate the speed in Test A.

2. Calculate the speed in Test B.

3. Calculate the speed in Test C.

4. Which test had the greatest speed?

Friction: Helpful or Unhelpful?

For each situation, decide whether friction is mainly helpful or mainly unhelpful. Then give one brief reason linked to the situation, such as grip, slowing motion, heat, or wear.

1. The grip between a shoe and the ground helps someone walk without slipping. Helpful or unhelpful, and why?

2. Friction between moving machine parts causes them to heat up and wear. Helpful or unhelpful, and why?

3. A bicycle’s brakes use friction to slow the wheels. Helpful or unhelpful, and why?

4. Air resistance slows a cyclist moving along a road. Helpful or unhelpful for travelling quickly, and why?

Pressure and Contact Area

Use pressure = force ÷ area. Pressure is measured in pascals (Pa) when force is in newtons and area is in square metres. For the same force, a smaller contact area produces greater pressure.

1. A force of 20 N acts on an area of 4 m². Calculate the pressure.

2. A force of 30 N acts on an area of 3 m². Calculate the pressure.

3. A force of 12 N acts on an area of 6 m². Calculate the pressure.

4. The same force acts on two surfaces: one has an area of 2 m² and the other 5 m². Which surface has the greater pressure?

Apply the Ideas

Use the science ideas from this worksheet to explain each situation. Keep each response focused: identify the relevant force or relationship and state what happens.

1. A box is pushed forwards with 15 N while friction acts backwards with 15 N. Describe what the balanced forces mean for the box’s motion if it is already moving at a steady speed.

2. A moving skateboard slows down when its rider stops pushing. Name the force that opposes its motion and describe its effect.

3. Why can a sharp drawing pin make a small mark when pushed with a modest force? Use the relationship between force, area and pressure.

Answer Key

Activity 1: 1. Balanced; 2. 5 N forwards; 3. 0 N; 4. 5 N to the right

Activity 2: 1. 6 m/s; 2. 5 m/s; 3. 4 m/s; 4. 2 m/s

Activity 3: 1. 5 m/s; 2. 6 m/s; 3. 3 m/s; 4. Test B

Activity 4: 1. Helpful: grip helps prevent slipping; 2. Unhelpful: friction causes heating and wear; 3. Helpful: friction slows the wheels; 4. Unhelpful: air resistance opposes motion and slows the cyclist

Activity 5: 1. 5 Pa; 2. 10 Pa; 3. 2 Pa; 4. The 2 m² surface

Activity 6: 1. The forces are balanced, so the box continues at a steady speed; 2. Friction (including resistance from the ground and air) opposes motion and slows the skateboard; 3. The pin’s small tip area produces high pressure for the applied force.