# A slender rod of mass  and length  is pivoted about a horizontal axis through one end and released from rest at an angle of 30  above the horizontal. The force exerted by the pivot on the rod are the instant when the rod passes through a horizontal position is a) along horizontal b)  along vertical c)  along a line making an angle of with the horizontal d) along a line making an angle of with the horizontal

## Question ID - 100213 | SaraNextGen Answer A slender rod of mass  and length  is pivoted about a horizontal axis through one end and released from rest at an angle of 30  above the horizontal. The force exerted by the pivot on the rod are the instant when the rod passes through a horizontal position is a) along horizontal b)  along vertical c)  along a line making an angle of with the horizontal d) along a line making an angle of with the horizontal

1 Answer - 5876 Votes

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Answer Key : (c) -

(c)

The angular velocity of the rod about the pivot when it passes through the horizontal position is given by

Radial acceleration of the centre of mass (as centre of mass is moving in a circle of radius  is given by

Torque about pivot, in the horizontal position, is

Tangential acceleration of the centre of mass,

Draw the FBD of the rod at an instant when it passes through the horizontal position. Use Newton’s second law of equation

So, reaction force by the pivot on the rod,

at an angle of  with the horizontal