Question

A person carries a mass of 10 kg and walks along the +x-axis for a distance of 100m with a constant velocity of 2 m/s. What is the work done by this person?
A) 20 J

B) None of the other choices is correct.

C) 0 J

D) 200 J

Answer 1

Answer:

Work done, W = 0

Explanation:

It is given that,

Mass of the object, m = 10 kg

Distance covered by the person, d = 100 m

Speed of the person, v = 2 m/s

We need to find the work done by this person. We know that the product of force and distance is equal to the work done by the person. Mathematically,

$W=F\times d$

$W=m\times a\times d$    

Since, the acceleration is equal to the rate of change of velocity. Here, the person is moving the mass with a constant velocity. So, there is no change in velocity, a = 0

As a result, the work done by the person is 0 J. So, the correct option is (c). Hence, this is the required solution.      

Answer 2

Since the direction of the force and the direction of the path is perpendicular, the person is not doing any physical work.