Practise 22 real questions on Forces/density/pressure from 2021 to 2026. See the answer and explanation as soon as you answer.
Forces/density/pressure is one of the 13 main topics in our A Level Physics (Cambridge (CAIE) 9702) question bank, and about 3% of its real questions come from it. Tayyari Karo has 22 real questions on this topic from 2021 to 2026, from Paper 1, Paper 2; 18 are multiple choice and marked instantly, and the rest are structured questions with a model answer. By difficulty: 12 medium, 8 easy, 2 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
An object is submerged in a liquid.
Which statement about the upthrust acting on the object is correct?
Answer: A. It is proportional to the density of the liquid.
Upthrust = ρgV, where ρ is the liquid density and V is the volume of liquid displaced.
A uniform cylinder of weight 25.0 N is suspended from a newton meter and fully submerged in water; the reading on the newton meter is 10.0 N. The water is replaced by a liquid of density 10% greater than water, with the cylinder remaining fully submerged.
What is the new reading on the newton meter?
Answer: A. 8.5 N
Upthrust in water = 25.0 − 10.0 = 15.0 N. New upthrust = 15.0×1.10 = 16.5 N. New reading = 25.0 − 16.5 = 8.5 N.
A uniform rod of weight 28 N is supported at one end by force F and is attached to a frictionless hinge at end X. The rod makes an angle of 40° with the horizontal at X; the weight 28 N acts vertically downward at the midpoint of the rod, and F acts perpendicular to the rod at its far end. What is the magnitude of F?
Answer: B. 11 N
Taking moments about X: F×L = 28×(L/2)cos40°, so F = 14cos40° ≈ 11 N.
A man of weight 600 N stands with both feet flat on the ground. What is a reasonable estimate of the pressure exerted on the ground by the weight of the man?
Answer: C. 1 × 10⁴ Pa
With a combined foot area of order 0.03–0.06 m², pressure = F/A ≈ 600/0.05 ≈ 1×10⁴ Pa.
Which expression for pressure is correct?
Answer: A. force per unit area
Pressure is defined as force per unit area (p = F/A).
A shelf XY is 0.40 m long, attached to a wall at end X, and kept horizontal by a wire from Y to the wall. The tension in the wire is 15 N at 30° to the horizontal. What is the moment of this force about point X?
Answer: A. 3.0 N m
Moment = F sinθ × length = 15 × sin30° × 0.40 = 3.0 N m.
| Session | Paper 1 | Paper 2 |
|---|---|---|
| May/June 2026 | 4 | 1 |
| May/June 2025 | 3 | 1 |
| October/November 2025 | 4 | 1 |
| May/June 2023 | 2 | 1 |
| October/November 2021 | 5 | – |
22 real A Level Physics (9702) questions on Forces/density/pressure from 2021 to 2026, from Paper 1, Paper 2. Each one shows the year, session and paper it came from.
Yes. Every question shows the correct answer and a short explanation the moment you answer.
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