Uniform Circular Motion

For an object to move in a circle, it must have a net force acting on it that is directed towards the center of the circle. This force is called the centripetal force. In the case of a car turning on a flat road, the static friction between the tires and the road provides the necessary centripetal force. Therefore, the direction of friction is towards the centre of the circular path.

(a) Which force produces negative moment?
By convention, a moment that tends to cause clockwise rotation is considered negative, and a moment that tends to cause anti-clockwise rotation is positive. - Force F tends to rotate the wheel in the clockwise direction. Therefore, F produces a negative moment. - Force F tends to rotate the wheel in the anti-clockwise direction. Therefore, F produces a positive moment.
(b) Is the wheel in equilibrium?
Yes, the wheel is in equilibrium.
(c) Justification:
For a body to be in rotational equilibrium, two conditions must be met:
1. Translational Equilibrium: The net force acting on the body must be zero. The forces F and F are equal in magnitude and opposite in direction. Thus, the net force is .
2. Rotational Equilibrium: The net moment (or torque) about the pivot point (O) must be zero. - Moment due to F is (clockwise, hence negative). - Moment due to F is (anti-clockwise, hence positive). - The net moment is . Since both the net force and the net moment are zero, the wheel is in a state of rotational equilibrium.