Rotational Motion (KVPY Stream SB-SX (Class 12 & 1st Year BSC) Physics): Questions 9 - 11 of 13

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Question number: 9

» Rotational Motion » Concepts of Rotational Motion

Appeared in Year: 2015

MCQ▾

Question

A uniform cylinder of mass M and radius R is rotated freely about a stationary horizontal axis O. On cylinder a cord of length l and mass m is wound in a single layer. The wound part of the cord is supposed to have it centre of gravity on the cylinder axis. The angular acceleration of the cylinder as a function of the length x of the hanging part of the cord is –

Choices

Choice (4) Response

a.

2mgxlR(M)

b.

mgxlR(M+m)

c.

mgxR(M+2m)

d.

2mgxlR(M+2m)

Question number: 10

» Rotational Motion » Moment of Inertia

MCQ▾

Question

A homogeneous sphere of mass M and radius R has moment of inertia I about its diameter. A concentric sphere of radius R4 is carved out from the sphere. What is the moment of inertia of the remaining part about the diameter?

Choices

Choice (4) Response

a.

94I

b.

8180I

c.

10231024I

d.

910I

Question number: 11

» Rotational Motion » Moment of Inertia

Appeared in Year: 2015

MCQ▾

Question

A horizontal disk of moment of inertia 4.25 kg-m2 with respect to its axis of symmetry is spinning counter clockwise at 15 revolutions per second about its axis, as viewed from above. A second disk of moment of inertia 1.80 kg-m2 with respect to its axis of symmetry is spinning clockwise at 25 revolutions per second as viewed from above about the same axis and is dropped on top of the first disk. The two disks stick together and rotate as one about their axis of symmetry. The new angular velocity of the system as viewed from above is close to.

Choices

Choice (4) Response

a.

18 revolutions per second and counter clockwise

b.

3 revolutions per second and clockwise

c.

3 revolutions per second and counter clockwise

d.

18 revolutions per second and clockwise

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