Physics Homework question?

Question

A Truck driver, recently tested a prototype race truck

whose mass is 3 tonne. The diesel engine is capable of exerting a constant force of 80.0 kN.

(a) Air resistance, road resistance and drag on the truck are negligible, calculate the acceleration of the truck on a horizontal stretch of Arizona desert.

(b)The Chief Engineer then made some alterations to the truck that allowed it to reach a speed of 43 m/s². Calculate the kinetic energy of the truck at this speed.

I'm thinking a=F/m for the first part, but the second one I'm lost although I know Ek=½mv²?

This is my son's homework question, so if you don't want to help fine, but please keep any comments to yourself then?

Answer 1

Given what you have said, I don't understand why you are "lost". Your formulae are indeed correct.

For the second part, you have v = 43 m/s (note: not m/s² - I assume you have simply mis-typed). One has to assume that the engineer's alterations have made no significant difference to the mass, it is still m = 3 tonnes. So you calculate Ek from your formula.

(The force is irrelevant to part b).