Question

A car accelerates on a horizontal road due to the force exerted by

• A. The engine of the car
• B. The driver of the car
• C. The earth
• D. The road

Answer 1

The correct option is D

The road

Explanation for the correct answer:

In the case of option D.

1. A car accelerates on a horizontal road solely due to the force exerted by the road on the car.
2. The tyres of the car accelerate on the road as the road try to push back the tires.
3. The road and the tyres, both push against each other at the same moment.
4. We know according to Newton’s third law of motion, as the car pushes the ground in the backward direction, and the ground’s reaction force pushes in the forward direction simultaneously acts on the car.
5. The frictional force plays a big role in this movement of the car.
6. Hence, option D is the correct option.

Explanation for the incorrect answers:

In the case of option A.

1. The engine directly does not apply force on the road or tire either.
2. It is the road that applies force in the forward direction in reaction to the force applied by the tyre on the road.
3. Hence, option A is the incorrect option.

In the case of option B.

1. Driver of the car does not exert any force on the car except his own weight.
2. He just controls the car.
3. Hence, option B is also an incorrect option.

In the case of option C.

1. Earth also does not exert any force in a forward or backward direction.
2. Hence, option C is the incorrect option.

Hence, option D is the correct option.