Rotational Motion Question 58
Question: A drum of radius R and mass M, rolls down without slipping along an inclined plane of angle $ \theta $ . The frictional force:
[AIPMT (S) 2005]
Options:
A) converts translational energy to rotational energy
B) dissipates energy as heat
C) decreases the rotational motion
D) decreases the rotational and translational motion
Show Answer
Answer:
Correct Answer: A
Solution:
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When a body rolls down without slipping along an inclined plane of inclination $ \theta , $ it rotates about a horizontal axis through its centre of mass and also its centre of mass moves.
Therefore, rolling motion may be regarded as a rotational motion about an axis through its centre of mass plus a translational motion of the centre of mass.
As it rolls down, it suffers loss in gravitational potential energy provided translational energy due to factional force is convened into rotational energy.
Note: In fact, friction is needed to cause the body to roll.
However the rolling friction is so small that we can use conservation of mechanical energy.
