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Column-I

Column- II

(A)

A small particle of mass  is given an initial velocity in horizontal plane and winds its cord around the fixed vertical shaft of radius

(p)

Conservation of angular momentum

(B)

A smooth rod rotates with some angular velocity. A small sleeve starts sliding along the rod

(q)

Conservation of kinetic energy

(C)

Two ice-skaters approach each other at equal speeds along the parallel path separated by some distance. They link hands as they pass by and pull each other to reduce their separation

(r)

Conservation of total mechanical energy

(D)

A small body tied to a non-stretchable thread of mass   is lying over a smooth horizontal plane. Other end of the thread is being drawn into a hole 

(s)

Work is done by internal forces

CODES :

 

A

B

C

D

 

 

a)

D,a

b

c,a

a,c

 

 

b)

c

d,a

b,a

b

 

 

c)

b,a

c

a,d

b

 

 

d)

b,c

a,b,c

a,d

a,d

 

 



Question ID - 100995 | SaraNextGen Top Answer

Column-I

Column- II

(A)

A small particle of mass  is given an initial velocity in horizontal plane and winds its cord around the fixed vertical shaft of radius

(p)

Conservation of angular momentum

(B)

A smooth rod rotates with some angular velocity. A small sleeve starts sliding along the rod

(q)

Conservation of kinetic energy

(C)

Two ice-skaters approach each other at equal speeds along the parallel path separated by some distance. They link hands as they pass by and pull each other to reduce their separation

(r)

Conservation of total mechanical energy

(D)

A small body tied to a non-stretchable thread of mass   is lying over a smooth horizontal plane. Other end of the thread is being drawn into a hole 

(s)

Work is done by internal forces

CODES :

 

A

B

C

D

 

 

a)

D,a

b

c,a

a,c

 

 

b)

c

d,a

b,a

b

 

 

c)

b,a

c

a,d

b

 

 

d)

b,c

a,b,c

a,d

a,d

 

 

1 Answer
127 votes
Answer Key / Explanation : (d) -

(d)

a. Angular momentum will not be conserved as  will provide torque about . Kinetic energy will remain conserved as tension is perpendicular to velocity and it does not do any work. Obviously, the total mechanical energy also remains conserved

b. Angular momentum remains conserved as no external torque acts. Mechanical energy and kinetic energy of (rod + sleeve) system will remain the same because no work is done by external forces and there is no dissipating force in the system

c. Angular momentum will remain conserved. Because there is no external force (friction is zero because of ice)

Kinetic energy and mechanical energy will decrease because of work done by internal forces (due to muscles) between the icekaters.

d. Angular momentum will remain conserved, because torque of  will be zero

 will do positive work on the block due to which kinetic energy and mechanical energy of the block will increase

127 votes


127