Final answer:
The net force acting on a 1000 kg car moving at a constant speed of 20 m/s with a forward force of 500N and frictional force of 400N is 100N.
Step-by-step explanation:
The question asks about the net force acting on a car with a mass of 1000 kg moving at a constant speed with a forward force provided by the engine and the counteracting frictional force. To find the net force, we subtract the frictional force from the forward force provided by the engine. In mathematical terms, the net force (F_net) is obtained by subtracting the frictional force (F_friction) from the engine force (F_engine):
F_net = F_engine - F_friction
In this case:
F_net = 500 N (forward force) - 400 N (frictional force)
So, the net force on the car is:
F_net = 100 N
Since the car is moving at a constant speed, this net force does not cause any acceleration according to Newton's first law. The net force is simply what would be required to overcome the frictional resistance and maintain the car's constant velocity.