A man does 4,475 J of work in the process of pushing his 2.50 103 kg truck from rest to a speed of v, over a distance of 26.0 m. Neglecting friction between truck and road, determine the following:

a. The speed v.
b. The horizontal force exerted on the truck.

a) 1.89 m/s  b) 172.1 N

Explanation:

a)

Applying the work-energy theorem, if we can neglect the friction between truck and road, the total change in kinetic energy must be equal to the work done by the external forces.This work, is just 4,475 J.So we can write the following equation:

       

where m= mass of the truck = 2.5*10³ kg.So, we can find the speed v, as follows:

       

b)

The work done by the man, is just the horizontal force applied, times the displacement produced by the force horizontally:

       

We can solve for F, as follows: