For each question: list what you know, decide which equation to use, then use FIFA. The solution starts by showing how to pick the equation.
Q1 (F) A cyclist travels 1200 m in 240 s at a steady speed. Calculate her speed.
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Which equation? Know distance and time, want speed → s = vt
I: 1200 = v × 240
A: v = 1200 ÷ 240 = 5.0 m/s
Q2 (F) A student has a mass of 65 kg. Calculate her weight.
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Which equation? Know mass, want weight → W = mg
I: W = 65 × 9.8
A: 637 N
Q3 (F) A 40 N force pushes a box 3.0 m across the floor. How much energy is transferred?
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Which equation? Know force and distance, want energy transferred (work done) → W = Fs
I: W = 40 × 3.0
A: 120 J
Q4 (F) A car speeds up from 5.0 m/s to 25 m/s in 8.0 s. Calculate its acceleration.
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Which equation? Know change in velocity and time, want acceleration → a = Δv / t
I: a = (25 − 5.0) ÷ 8.0
A: 2.5 m/s²
Q5 (F) A resultant force of 1500 N acts on a 1200 kg car. Calculate its acceleration.
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Which equation? Know force and mass, want acceleration → F = ma
I: 1500 = 1200 × a
F: a = 1500 ÷ 1200
A: 1.25 m/s²
Q6 (F) A spring with a spring constant of 40 N/m is stretched by 0.15 m. What force is stretching it?
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Which equation? Know spring constant and extension, want force → F = ke
I: F = 40 × 0.15
A: 6.0 N
Q7 (F/H, S only) A crate with a weight of 800 N rests on a base of area 0.50 m². Calculate the pressure on the floor.
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Which equation? Know force and area, want pressure → p = F / A
I: p = 800 ÷ 0.50
A: 1600 Pa
Q8 (F/H, S only) A mechanic pushes on a spanner with a force of 30 N, 25 cm from the nut. Calculate the moment.
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Which equation? Know force and distance from a pivot, want turning effect → M = Fd
Convert: 25 cm = 0.25 m
I: M = 30 × 0.25
A: 7.5 N m
Q9 (F/H) A ball is dropped from rest and falls 20 m. Calculate its speed just before it hits the ground. (Ignore air resistance; acceleration = 9.8 m/s².)
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Which equation? Know initial velocity (0), acceleration and distance, no time given, want final velocity → v² − u² = 2as
I: v² − 0² = 2 × 9.8 × 20
F: v² = 392, v = √392
A: 19.8 m/s (3 s.f.)
No time given is the clue for this equation.
Q10 (H) A 70 kg sprinter runs at 9.0 m/s. Calculate her momentum.
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Which equation? Know mass and velocity, want momentum → p = mv (careful: not kinetic energy!)
I: p = 70 × 9.0
A: 630 kg m/s
Q11 (H) A 900 kg car slows from 20 m/s to rest in 4.0 s. Calculate the average braking force.
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Which equation? Know mass, change in velocity and time, want force. Two routes:
Route 1 (C+S): a = Δv / t = 20 ÷ 4.0 = 5.0 m/s², then F = ma = 900 × 5.0
Route 2 (S only): F = mΔv / Δt = 900 × 20 ÷ 4.0
A: 4500 N
Q12 (H, S only) A diver is 2.0 m below the surface of a pool. The density of water is 1000 kg/m³. Calculate the pressure due to the water.
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Which equation? Know depth and density of a liquid, want pressure → p = hρg (not p = F/A – no force or area given)
I: p = 2.0 × 1000 × 9.8
A: 19 600 Pa
