Three students A, B and C drag identical wooden boxes along the same straight 10 ,m…
PHYSICS · Subjective · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
Three students A, B and C drag identical wooden boxes along the same straight 10\,m school corridor. In every case the pulling force has the same magnitude 50N, but the directions differ.
• Student A pulls horizontally, parallel to the corridor.
• Student B pulls using a rope that makes an angle of 60∘ above the corridor direction.
• Student C pulls using a rope that makes an angle of 120∘ to the corridor direction (i.e. the pull is partly backward).
Answer the following:
(i) For each student state whether the work done by the pulling force is positive, negative or zero.
(ii) Without actually multiplying the numbers, arrange the magnitudes of work done in descending order, giving a brief reason based on the angle involved.
(iii) Explain why the ranking obtained in part (ii) is valid even though the numerical values of work were not calculated explicitly.