WAEC 2019 Physics · Question 27

The mass of a load is doubled while the force acting on it is halved. The resulting acceleration of the load is

Options

A.quadrupled
B.quartered
C.halved
D.doubled

Answer: B. quartered

Explanation written with AI and checked against the answer key

Analyze the question The mass is doubled and the force is halved. We need to find how the acceleration changes. Concept Newton's Second Law of Motion: F = ma, so a = F/m. Acceleration is directly proportional to force and inversely proportional to mass. Solution Original acceleration: a₁ = F/m New mass: m₂ = 2m New force: F₂ = F/2 New acceleration: a₂ = F₂/m₂ = (F/2) / (2m) = F/(4m) Compare with the original: a₂ = (1/4)(F/m) = a₁/4 The acceleration becomes one quarter of its original value, so it is quartered. Answer Tip For "ratio" questions like this, just multiply the change factors. Force contributes a factor of ½ (it is in the numerator), and mass contributes a factor of ½ (it is in the denominator, so doubling it gives ½). Then ½ × ½ = ¼. Always ask: is the quantity on top or bottom of the formula?

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