Concepts Of Physics MCQ Edition [Volume 1]
- Exam
- Concepts Of Physics MCQ Edition [Volume 1]
- Subject
- Physics
- Chapter
- Rotational Mechanics
Concepts Of Physics MCQ Edition [Volume 1] · Physics · Rotational Mechanics
For rear-wheel drive cars, the engine turns the rear wheels,...
For rear-wheel drive cars, the engine turns the rear wheels, whereas the front wheels rotate solely because the car moves. When such a car accelerates along a horizontal road, the friction
Options
- Aon the front wheels acts in the backward direction
- Bon the rear wheels possesses a larger magnitude than the friction on the front wheels
- Con the car acts in the backward direction
- Don the rear wheels acts in the forward direction
Correct answer
D. on the rear wheels acts in the forward direction
Step-by-step solution
For a rear-wheel drive car, the engine applies a torque to the rear wheels, causing them to tend to slip backward at the point of contact with the road. To oppose this slipping, the static friction on the rear wheels acts in the forward direction. This forward friction provides the driving force for the car.
The front wheels are not driven by the engine. They are pushed forward by the axle. To make them roll and provide angular acceleration, friction at the point of contact must act in the backward direction.
Since the car is accelerating forward, the net external force must be in the forward direction. The net force is the vector sum of the friction on the rear wheels (forward) and the front wheels (backward). Therefore, the magnitude of the forward friction on the rear wheels must be greater than the backward friction on the front wheels.
The front wheels are not driven by the engine. They are pushed forward by the axle. To make them roll and provide angular acceleration, friction at the point of contact must act in the backward direction.
Since the car is accelerating forward, the net external force must be in the forward direction. The net force is the vector sum of the friction on the rear wheels (forward) and the front wheels (backward). Therefore, the magnitude of the forward friction on the rear wheels must be greater than the backward friction on the front wheels.