Year 9 Forces Worksheet - Intermediate

Year 9 Forces worksheet for Year 9 (Key Stage 3 / Year 7-9 (Ages 11-14)). Intermediate 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)•Forcesintermediate

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Forces in Action: Year 9

Key Stage 3 Science | Ages 13–14 | Intermediate

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Instructions: Use the equations and data provided, showing your working where calculations are needed. Include units in numerical answers and use scientific vocabulary precisely. The activities cover motion, pressure, moments and different types of force.

Speed and Distance

Use speed = distance ÷ time. Convert units where needed before calculating, and write the correct unit in each answer.

1. A cyclist travels 600 m in 120 s. Calculate the cyclist’s average speed in m/s.

2. A car travels 150 km in 2.5 h. Calculate its average speed in km/h.

3. A runner moves at 4 m/s for 90 s. Calculate the distance travelled.

4. A train travels 18 km at an average speed of 12 m/s. Calculate the time taken in seconds.

Interpreting a Distance–Time Graph

Use the distance–time data in the table as points on a graph, with time on the horizontal axis and distance on the vertical axis. Plot the points and join consecutive points with straight lines, then answer the questions. A steeper line represents a greater speed; a horizontal line represents no change in distance.

Time (min)	Distance from start (m)
0	0
2	120
4	240
6	240
8	360

1. Plot the five data points and join them in order.

2. What was the object’s speed from 0 to 4 minutes, in m/min?

3. During which time interval was the object stationary?

4. What was its speed from 6 to 8 minutes, in m/min?

Relative Motion

For objects moving in the same direction, subtract their speeds to find their relative speed. For objects moving towards one another, add their speeds. Give each answer with a suitable unit.

1. Two cyclists travel in the same direction at 8 m/s and 5 m/s. What is their relative speed?

2. Two cars travel towards one another at 18 m/s and 22 m/s. What is their closing speed?

3. A bus moving at 15 m/s overtakes a car moving in the same direction at 11 m/s. How long does the bus take to gain 80 m on the car?

Pressure in Solids, Liquids and Gases

For a solid surface, use pressure = force ÷ area. For pressure in a liquid, use pressure difference = density × gravitational field strength × depth. Use g = 10 N/kg and water density = 1,000 kg/m³. State pressure in pascals (Pa).

1. A box exerts a force of 240 N on an area of 0.12 m². Calculate the pressure on the floor.

2. A student applies a force of 500 N through a heel area of 0.002 m². Calculate the pressure on the ground.

3. Calculate the increase in water pressure at a depth of 2.5 m.

4. A sealed syringe contains gas. The plunger is pushed in, reducing the gas volume while its temperature stays constant. Does the gas pressure increase or decrease?

Moments and Levers

Calculate a moment using moment = force × perpendicular distance from the pivot. Give moments in newton-metres (N m). For a balanced lever, clockwise moments equal anticlockwise moments.

1. A 30 N force acts perpendicular to a lever 0.40 m from its pivot. Calculate its moment.

2. A spanner is 0.25 m long. A perpendicular force of 80 N is applied at its end. Calculate the moment about the nut.

3. A balanced seesaw has a 200 N child sitting 1.5 m from the pivot on one side. A second child sits 2.0 m from the pivot on the other side. Calculate the second child’s weight.

Contact and Non-contact Forces

Classify each force as contact or non-contact. Then identify the named force acting in each situation. A force may act without objects touching when it is a non-contact force.

1. A book rests on a table. Classify the upward support force from the table as contact or non-contact.

2. Earth pulls a falling apple towards the ground. Name this force and classify it as contact or non-contact.

3. A magnet attracts an iron nail across a small gap. Name this force and classify it as contact or non-contact.

4. Air resistance acts on a moving cyclist. Classify this force as contact or non-contact.

Answer Key

Activity 1: 1. 5 m/s ; 2. 60 km/h ; 3. 360 m ; 4. 1,500 s

Activity 2: 1. Plot and join (0, 0), (2, 120), (4, 240), (6, 240), (8, 360) ; 2. 60 m/min ; 3. 4–6 min ; 4. 60 m/min

Activity 3: 1. 3 m/s ; 2. 40 m/s ; 3. 20 s

Activity 4: 1. 2,000 Pa ; 2. 250,000 Pa ; 3. 25,000 Pa ; 4. Increase

Activity 5: 1. 12 N m ; 2. 20 N m ; 3. 150 N

Activity 6: 1. Contact ; 2. Gravitational force (weight), non-contact ; 3. Magnetic force, non-contact ; 4. Contact