Rigid Body Dynamics

The net moment of the body is zero that means the distance between the force and the rotational axis is zero.

• The first part of the statement is false and other part is true

• The first part of the statement is false and other part is false too

• The first part of the statement is true and other part is false

• The first part of the statement is true and other part is true too

Answer explanation

The net moment of the body is zero that doesn’t mean that the distance between the force and the rotational axis is zero. This means moments caused by different forces cancels out. If this happens there is no motion of the body along with any direction and hence the body is said to be in equilibrium.

Suppose a gymnast is sitting on a rotating chair and his arms are outstretched. If he suddenly shortens his arms, what will happen?

• angular velocity will decrease

• moment of inertia will decrease

• angular velocity will stay constant 

• angular momentum will increase.

For the conditions of the equilibrium of the body, i.e. the rigid body only the external forces defines the equilibrium. Because the internal forces cancels out so not to be considered.

• The first part of the statement is false and other part is true

• The first part of the statement is false and other part is false too

• The first part of the statement is true and other part is false

• The first part of the statement is true and other part is true too

Answer explanation

The application of the internal forces does affect the conditions of the equilibrium of the body. Not only the external but the internal forces that are developed by the sake of external forces does develop a tending effect on the equilibrium of the body. Thus the internal forces doesn’t cancels out.

A particle is in UCM (uniform circular motion). Its angular momentum remains intact about:

• middle point of the circle 

• at any point within the circle 

• circumference point of the circle 

• at any point exterior to the circle.

A closed vessel of cylindrical shape is partly filled with water. If the vessel rotates along a horizontal plane around the perpendicular bisector, the moment of inertia ________

Draw a FBD of member ABC, which is supported by a smooth collar at A, roller at B, and link CD.

Answer explanation

If an object's angular velocity is increased by 10 percent, then K.E must be increased by what percentage?

Maintaining constant velocity, a particle is traveling down a line that is parallel to X-axis (positive). What will be the angular momentum magnitude with regards to origin?

• zero

• increasing along with x 

• decreasing along with x 

• remains constant