The weight of the car in the picture of the computer screen is 9,800 Newton's.
(a) Let's convert the final speed of the car in m/s:
The kinetic energy of the car at t=19 s is
(b) The average power delivered by the engine of the car during the 19 s is equal to the work done by the engine divided by the time interval:
But the work done is equal to the increase in kinetic energy of the car, and since its initial kinetic energy is zero (because the car starts from rest), this translates into
(c) The instantaneous power is given by
where F is the force exerted by the engine, equal to F=ma.
So we need to find the acceleration first:
And the problem says this acceleration is constant during the motion, so now we can calculate the instantaneous power at t=19 s:
You press the button near their answer
There can be someone who think answer should be B but temperature isn' proportional with heat. The formula is Q=m.c.t , so it isn't definetly temperature. So answer should be D. Because A and C connect with force etc.