Chapter 11, Problem 75A

To determine

To identify: Whether the car engine or truck engine will do more work.

Answer to Problem 75A

The truck engine will do more work.

Explanation of Solution

Given:

Both the vehicles are travelling at the same velocity.

Formula used:

According to work-energy theorem,

  $W=\Delta KE=\frac{1}{2}m(v_f{}^2-v_i{}^2)$

Calculation:

Consider,

Mass of car = $m$

Mass of truck = $M$

So, the kinetic energies for both the vehicles will be:

Kinetic energy of car = $\frac{1}{2}m{v}^2$

Kinetic energy of truck = $\frac{1}{2}M{v}^2$

A truck has greater mass, so it will have more kinetic energy.Using the work-energy theorem, it concludes that truck engine will do more work than car engine as the kinetic energy of truck is more than the car.

Conclusion:

Thus, the truck engine will do more work.