Rotational Motion And Torque
11 previous year questions.
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Chapter Questions 11 MCQs
A pendulum is made of a massless string of length and a small bob of negligible size and mass . It is released making an angle (<< 1 rad) from the vertical. When passing through the vertical, the string slips a bit from the pivot so that its length increases by a small amount ( ) in negligible time. If it swings up to angle on the other side before starting to swing back, then to a good approximation, which of the following expressions is correct? 
A uniform rigid meter-scale is held horizontally with one of its end at the edge of a table and the other supported by hand. Some coins of negligible mass are kept on the meter scale as shown in the figure. As the hand supporting the scale is removed, the scale starts rotating about its edge on the table and the coins start moving. If a photograph of the rotating scale is taken soon after, it will look closest to: 
A uniform rigid meter-scale is held horizontally with one of its end at the edge of a table and the other supported by hand. Some coins of negligible mass are kept on the meter scale as shown in the figure. As the hand supporting the scale is removed, the scale starts rotating about its edge on the table and the coins start moving. If a photograph of the rotating scale is taken soon after, it will look closest to: 
(Take the length of the day before the increment as 24 hours. Assume the Earth to be a sphere with uniform density.)
The angular momentum of a particle relative to the origin varies with time ( ) as , where . The angle between and the torque acting on the particle becomes after a time of ............ s.