a car of mass 1200 kg starts from rest, accelerates uniformly to a speed 4ms-1 in 2 seconds and continues moving at this constant speed in a horizontal straight line for additional 10s.

Question

the brakes are then applied and the car is brought to rest in 4s. a constant resistance force of 500 N is acting on the car during its entire motion.
a) calculate the force accelerating the car in first 2 sec of the motion
b) calculate the average power developed by the engine in the first 2 sec of the motion
c) calculate the force pushing the car forward in the next 10 sec
d) calculate the power developed by the engine in those 10 sec
e) calculate the braking force in the last 4s of the motion
f) describe the energy transformations that have taken place in the 16s of the motion of the car.
please, i need it in 3 hours

Answer 1

a) force=ma
b)power=force*distance/time=ma*1/2 a t
c)constant speed: force=500N
d) you do these, I can check you, all are pretty straightforwrd