Statement (1): Damping force does depend on the medium through which the object is moving. A denser medium creates more resistance, leading to a greater damping force.
Statement (2): This is correct. The damping force is generally proportional to the velocity of the body, as described by \( F_{\text{damping}} = -b v \), where \( b \) is a damping coefficient and \( v \) is the velocity.
Statement (3): This statement is incorrect. The damping force always acts opposite to the direction of the velocity of the body, not in the same direction.
Statement (4): This is true. The damping force also depends on factors such as the size and shape of the body because they influence the drag force in the medium.
Conclusion: Statement (3) is incorrect, making it the right answer. The correct answer is (3).
Final Answer: \[ \boxed{\text{Damping force acts in the direction of the velocity of the body.}} \]
The center of a disk of radius $ r $ and mass $ m $ is attached to a spring of spring constant $ k $, inside a ring of radius $ R>r $ as shown in the figure. The other end of the spring is attached on the periphery of the ring. Both the ring and the disk are in the same vertical plane. The disk can only roll along the inside periphery of the ring, without slipping. The spring can only be stretched or compressed along the periphery of the ring, following Hooke’s law. In equilibrium, the disk is at the bottom of the ring. Assuming small displacement of the disc, the time period of oscillation of center of mass of the disk is written as $ T = \frac{2\pi}{\omega} $. The correct expression for $ \omega $ is ( $ g $ is the acceleration due to gravity):