Question

A car is moving with speed of 40km/h. If the car engine generates 7 kilowatt power, then the resistance in the path of motion of the car will be

Answer 1

Power = Force × speed.
Here in this case The engine has to deliver Power against Resistance (Force) to maintain a constant speed .

Resistance = Power/speed;
_____________
Given :
Power = 7 kW = 7000W
Speed = 40km/h = 40×(5/18) m/s.
= 11.11 m/s
_____________

Resistance = 7000/11.11
= 630.063 N
_____________
hope it helps!