Rotational Motion (NEET (National Eligibility cum Medical Entrance Test) Physics): Questions 7  12 of 125
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Question number: 7
» Rotational Motion » Torque
Question
A child is standing with folded hands at the center of a platform rotating about its central axis. The kinetic energy of the system is K. The child now stretches his arms so that the moment of inertia of the system doubles. The kinetic energy of the system now is
(1) Less than 2K
(2) Equal to K/2
(3) More than K/4
(4) Equal to 4K
Select the correct answers and mark it according to the following codes:
Choices
Choice (4)  Response  

a. 
1, 2 and 3 are correct 

b.  2 and 4 are correct 

c.  1 and 3 are correct 

d. 
1 and 2 are correct 

Question number: 8
» Rotational Motion » Torque
Question
A constant torque acting on a uniform circular wheel changes its angular momentum from Aq to 4Aq in 4 seconds. The magnitude of this torque is
Choices
Choice (4)  Response  

a. 


b. 


c. 


d. 


Passage
Consider a cylinder of mass M = 1kg and radius R = 1 m lying on a rough horizontal plane. It has a plank lying on its top as shown in the figure.
A force F = 55 N is applied on the plank such that the plank moves and causes the cylinder to roll. The plank always remains horizontal. There is no slipping at any point of contact.
Question number: 9 (1 of 3 Based on Passage) Show Passage
» Rotational Motion » Angular Momentum
Question
Find the value of frictional force at B
Choices
Choice (4)  Response  

a.  5.0N 

b.  2.5 N 

c.  7.5 N 

d.  None of the above 

Question number: 10 (2 of 3 Based on Passage) Show Passage
» Rotational Motion » Angular Momentum
Question
Calculate the acceleration of cylinder.
Choices
Choice (4)  Response  

a.  10 m/s ^{2} 

b.  5 m/s ^{2} 

c.  20 m/s ^{2} 

d.  Question does not provide sufficient data or is vague 

Question number: 11 (3 of 3 Based on Passage) Show Passage
» Rotational Motion » Angular Momentum
Question
Find the value of frictional force at A
Choices
Choice (4)  Response  

a.  2.5 N 

b.  7.5 N 

c.  5.0 N 

d.  None of the above 

Question number: 12
» Rotational Motion » Torque
Question
A constant torque of 700 N m, turns a wheel of moment of inertia 50 kg m ^{2} about an axis passing through the center. Angular velocity of the wheel after 2 s will be
Choices
Choice (4)  Response  

a.  1 rad/s 

b.  15 rad/s 

c.  28 rad/s 

d.  5 rad/s 
