Home
Class 12
PHYSICS
A : rigid body can't be in a pure rollin...

A : rigid body can't be in a pure rolling on a rough inclined plane without giving any external force.
R : Since there is no torque providing force acting on the body in the above case, the body can't come in a rolling condition.

A

If both Assertion & Reason are true and the reason is the correct explanation of the assertion,

B

If both Assertion & Reason are true but the reason is not the correct explanation of the assertion,

C

If Assertion is true statement but Reason is false,

D

If both Assertion and Reason are false statements,

Text Solution

AI Generated Solution

The correct Answer is:
To analyze the statements given in the question, we will break down the reasoning step by step. ### Step 1: Understanding the Statements - **Statement A**: A rigid body cannot be in pure rolling on a rough inclined plane without giving any external force. - **Statement R**: Since there is no torque providing force acting on the body in the above case, the body can't come in a rolling condition. ### Step 2: Analyzing Statement A A rigid body, such as a disc or a sphere, can roll down a rough inclined plane without the need for any external force. The force of gravity acting on the body will cause it to roll. The component of gravitational force acting down the incline is given by \( mg \sin \theta \), where \( m \) is the mass of the body and \( \theta \) is the angle of the incline. **Conclusion for Statement A**: This statement is **false** because a rigid body can indeed roll down a rough inclined plane without requiring any external force. ### Step 3: Analyzing Statement R The reason provided states that there is no torque providing force acting on the body, and thus it cannot roll. However, the gravitational force acting on the body does create a torque about the point of contact with the inclined plane. The torque due to the gravitational force is given by: \[ \tau = r \cdot F \] Where \( r \) is the radius of the body and \( F \) is the component of the weight acting perpendicular to the radius, which is \( mg \sin \theta \). **Conclusion for Statement R**: This statement is also **false** because the gravitational force does create a torque that allows the body to roll. ### Step 4: Final Conclusion Both statements A and R are false. Therefore, the correct answer is that neither statement is true.
Promotional Banner

Similar Questions

Explore conceptually related problems

A disc can roll wihtout slippingg, without applying any external force on a

A body is in pure rolling on a surface. Is it necessarily being acted upon by an external torque ?

When a body is lying on a rough inclined plane and does not move, the force of friction

A body is placed on a rough inclined plane of inclination theta . As the angle theta is increased from 0^(@) to 90^(@) the contact force between the block and the plane

When a body rolls without sliding up an inclined plane the frictional force is :

A body of mass m is kept on a rough fixed inclined plane of angle of inclination theta=30^(@) . It remains stationary. Then magnitude of force acting on the body by the inclined plane is equal to :

A body of mass 10 kg is lying on a rough inclined plane of inclination 37^(@) and mu = 1//2 , the minimum force required to pull the body up the plane is

A body of mass m is released from the top of a rough inclined plane as shown in figure. If the frictional force be F, then body will reach the bottom with a velocity

Three bodies, a ring, a soild cylinder and a soild sphere roll down the same inclined plane without slipping. They start from rest. The radii of the bodies are identical. Which of the bodies reaches the ground with maximum velocity ?