Question

A man moves on a straight horizontal road with a block of mass 2 kg in his hand. He covers a distance 40m with an acceleration of 0.5m/s^2 .

We have to find the work done by the man on the block.

Can we consider the situation above as a non-inertial frame? The man is accelerating forward, therefore, a pseudo force will act on the box in the opposite direction which will be equal to

F = ma = 2*0.5 = 1N

And since the force is in the opposite direction to that of the distance covered, the work done by the force will be negative i.e. -40J. Where is this approach lacking since the answer is not negative? The answer is 40J.

Answer 1

The work done by the man on the block is positive because the force he applies to accelerate the block is in the same direction as the displacement, resulting in positive work of 40 J.

Step-by-step explanation:

The scenario presents a non-inertial reference frame due to the man's acceleration. However, when considering the work done by the man on the block, we should focus on the force he applies in the direction of the block's displacement. In this case, the man does positive work since he moves the block in the direction of his movement. If we ignore other forces like gravity and friction since they are not specified in the problem, the work done by the man is not negative. The calculation of work should take into account the actual force exerted by the man on the block in the direction of the block's displacement, which is not provided in the question but assumed to be equal to the force necessary to accelerate the block, making the work done positive and equal to 40 J.