NTA Abhyas JEE Main2020PhysicsLaws of MotionPractice
A car is moving along the circle x 2 + y 2 = a 2 in the anti-clockwise direction with a constant speed. The x - y plane is a rough horizontal stationary surface. When the car is at the point ( a cos θ , a sin θ ) , the unit vector in the direction of the friction force acting on the car is
Options
- Acos θ i ^ + sin θ j ^
- Bcos θ   i ^ - sin θ   j ^
- C- cos θ i ^ - sin θ j ^
- D- cos θ   i ^ + sin θ   j ^
Correct answer
C. - cos θ i ^ - sin θ j ^
Step-by-step solution
The direction of the friction force should be towards the centre of the circle which is - r ^ = - cos θ i ^ - sin θ j ^