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(C) The work done by a force is given by the formula $W = F \cdot s \cdot \cos(	heta)$,where $F$ is the force applied,$s$ is the displacement,and $

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Lifts it vertically upwards

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(C) The work done by a force is given by the formula $W = F \cdot s \cdot \cos(	heta)$,where $F$ is the force applied,$s$ is the displacement,and $	heta$ is the angle between the force and the displacement vector.When a man carries a load on his head,he must apply an upward force equal to the weight of the load $(F = mg)$ to counteract gravity.If he moves the load horizontally,the displacement is perpendicular to the force of gravity (the force he applies to hold the load),so $	heta = 90^\circ$. Since $\cos(90^\circ) = 0$,the work done against gravity is $0$.If he lifts the load vertically upwards,the displacement is in the same direction as the force applied,so $	heta = 0^\circ$. Since $\cos(0^\circ) = 1$,the work done is $W = F \cdot s = mgs$.Therefore,the maximum work is done when he lifts the load vertically upwards.

$A$ man carries a load on his head through a distance of $5 \,m$. The maximum amount of work is done when he ..........

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