Question 1Warm-upFoundation
Two people push a box to the right with forces of 40 N and 25 N. What is the resultant force?
Both forces act the same way, so add them.
Worked solution
- N to the right
Answer: N to the right
GCSE & IGCSE physics practice
Resultant force questions and answers
The resultant force is the single force that has the same effect as all the forces on an object together. Along a straight line, add forces in one direction and subtract those in the opposite direction. If the resultant is zero, the forces are balanced and the object stays still or keeps moving at a steady speed.
8 questions · Foundation and Higher tier · Every answer is checked as you type it, with a full worked solution. Updated .
Where resultant force comes up
| GCSE (AQA) | Physics and Combined Science, Foundation and Higher: calculate the resultant of forces acting in a line. Higher: resolve forces using scale vector diagrams. |
|---|---|
| Cambridge IGCSE (0625) | Core: determine the resultant of two or more forces along the same straight line, and know an object stays at rest or at constant speed unless a resultant force acts. |
The method
- Choose one direction as positive (for example to the right).
- Add the forces in that direction and subtract the forces in the opposite direction.
- State the size and the direction of the resultant.
- Zero resultant: balanced forces, so no change in speed or direction.
Resultant force questions
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Warm-up
Question 2Warm-upFoundation
A box is pushed right with 50 N while friction acts left with 30 N. What is the size of the resultant force?
Opposite directions: subtract.
Worked solution
- N
- The larger force is to the right, so the resultant is N to the right.
Answer: N to the right
Exam-style
Question 3Exam-styleFoundation
A car's engine gives a driving force of 2400 N. Air resistance is 900 N and friction is 300 N. Calculate the resultant force on the car.
Both resistive forces act backwards.
Worked solution
- Backward forces: N
- Resultant N forwards
Answer: N forwards
Question 4Exam-styleFoundation
A skydiver falls at a steady speed. Their weight is 750 N. What is the air resistance on them?
Steady speed means the forces are balanced.
Worked solution
- Constant speed, so the resultant force is zero.
- Air resistance weight N, acting upwards.
Answer: N upwards
Question 5Exam-styleFoundation
A tug pulls a boat forwards with 5000 N. The resultant force on the boat is 1800 N forwards. What is the total backward force from the water?
Forward force − backward force = resultant.
Worked solution
- N
Answer: N
Question 6Exam-styleFoundation
A lift has a weight of 6000 N. The cable pulls it up with 6500 N. What is the resultant force, and which way does it act?
Compare the upward pull with the weight.
Worked solution
- N
- The upward force is bigger, so the resultant is N upwards (the lift accelerates upwards, or slows if moving down).
Answer: N upwards
Challenge
Question 7ChallengeFoundation
Three forces act on a sledge along the same line: 120 N forwards, 45 N backwards and 30 N backwards. Calculate the resultant force.
Total the backward forces first.
Worked solution
- Backwards: N
- Resultant N forwards
Answer: N forwards
Question 8ChallengeHigher
Two forces act on an object at right angles: 6 N east and 8 N north. Calculate the size of the resultant force.
At right angles, use Pythagoras.
Worked solution
- N
Answer: N
Common mistakes
- Adding forces that act in opposite directions.
- Forgetting to give the direction of the resultant.
- Thinking a moving object must have a resultant force on it (constant speed means balanced forces).
Stuck on one of these?
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Sources
The questions are our own. The “where it comes up” notes are from each board's published specification, checked on 27 October 2026:
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