Answer:
d. a is correct but b is wrong.
Step-by-step explanation:
A car that is moving at a constant speed of 10m/s is experiencing a net force of zero, meaning that the sum of all forces acting on the car is equal to zero. This means that the forward force applied by the engine is equal in magnitude but opposite in direction to the force of friction acting on the car.
The force of friction acts to slow down the car, but it does not equal the forward force applied by the engine. Instead, it is determined by factors such as the weight of the car, the road surface, and the tire traction. If the forward force applied by the engine is greater than the force of friction, the car will accelerate. Conversely, if the force of friction is greater than the forward force applied by the engine, the car will decelerate.