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Force from Work and Distance
Use the Physics Equations Sheet to answer this question. The child pushed the baby walker 2.8 m across a horizontal floor. The work done by the child was 35 J.
Calculate the horizontal force the child applied to the baby walker.
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Marking points
- 1 Substitutes the work done and distance into W = Fs.
- 2 Rearranges correctly for force.
- 3 Gives 12.5 N, with 13 N accepted.
Full-mark answer
W = Fs, so 35 = F × 2.8. Therefore F = 35 ÷ 2.8 = 12.5 N.
Why this answer loses marks
Multiplies the work done by the distance.
Force is the unknown in the work equation, so the work done must be divided by distance.