Friction
PHXI05:LAWS OF MOTION

363347 A long block \(A\) of mass \(M\) is at rest on a smooth horizontal surface. A small block \(B\) of mass \(M / 2\) is placed on \(A\) at one end and projected along \(A\) with some velocity \(v\). The coefficient of friction between the block is \(\mu\). Then, the accelerations of blocks \(A\) and \(B\) before reaching a common velocity will be respectively
supporting img

1 \(\dfrac{\mu g}{2}\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
2 \(\mu g\) (towards right), \(\mu g\) (towards left)
3 \(\dfrac{\mu g}{2}\) (towards right), \(\mu g\) (towards left)
4 \(\mu g\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
PHXI05:LAWS OF MOTION

363348 Assertion :
The value of dynamic friction is less than the limiting friction.
Reason :
Once the motion has started, the inertia of rest has been overcome in case of friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI05:LAWS OF MOTION

363349 Statement A :
Kinetic friction always opposes the relative motion between the surfaces.
Statement B :
Static friction opposes or supports the motion.

1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
PHXI05:LAWS OF MOTION

363350 Find the maximum value of (\(M\)/\(m\)) in the situation shown in figure so that the system remains at rest. Friction coefficient of both the contacts is\(\mu \), string is massless and pulley is frictionless.
supporting img

1 \(\frac{{\sin \theta }}{{\sin \theta - \mu \cos \theta }}\)
2 \(\frac{{\cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
3 \(\frac{\mu }{{\sin \theta - \mu \cos \theta }}\)
4 \(\frac{{\mu \cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
PHXI05:LAWS OF MOTION

363351 If a block takes thrice as much time to slide down a \({\rm{45}}^\circ \) rough inclined plane as it takes to slide down a similar smooth plane. Then coefficient of friction is

1 \(\frac{1}{3}\)
2 \(\frac{2}{3}\)
3 \(\frac{9}{8}\)
4 \(\frac{8}{9}\)
PHXI05:LAWS OF MOTION

363347 A long block \(A\) of mass \(M\) is at rest on a smooth horizontal surface. A small block \(B\) of mass \(M / 2\) is placed on \(A\) at one end and projected along \(A\) with some velocity \(v\). The coefficient of friction between the block is \(\mu\). Then, the accelerations of blocks \(A\) and \(B\) before reaching a common velocity will be respectively
supporting img

1 \(\dfrac{\mu g}{2}\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
2 \(\mu g\) (towards right), \(\mu g\) (towards left)
3 \(\dfrac{\mu g}{2}\) (towards right), \(\mu g\) (towards left)
4 \(\mu g\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
PHXI05:LAWS OF MOTION

363348 Assertion :
The value of dynamic friction is less than the limiting friction.
Reason :
Once the motion has started, the inertia of rest has been overcome in case of friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI05:LAWS OF MOTION

363349 Statement A :
Kinetic friction always opposes the relative motion between the surfaces.
Statement B :
Static friction opposes or supports the motion.

1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
PHXI05:LAWS OF MOTION

363350 Find the maximum value of (\(M\)/\(m\)) in the situation shown in figure so that the system remains at rest. Friction coefficient of both the contacts is\(\mu \), string is massless and pulley is frictionless.
supporting img

1 \(\frac{{\sin \theta }}{{\sin \theta - \mu \cos \theta }}\)
2 \(\frac{{\cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
3 \(\frac{\mu }{{\sin \theta - \mu \cos \theta }}\)
4 \(\frac{{\mu \cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
PHXI05:LAWS OF MOTION

363351 If a block takes thrice as much time to slide down a \({\rm{45}}^\circ \) rough inclined plane as it takes to slide down a similar smooth plane. Then coefficient of friction is

1 \(\frac{1}{3}\)
2 \(\frac{2}{3}\)
3 \(\frac{9}{8}\)
4 \(\frac{8}{9}\)
PHXI05:LAWS OF MOTION

363347 A long block \(A\) of mass \(M\) is at rest on a smooth horizontal surface. A small block \(B\) of mass \(M / 2\) is placed on \(A\) at one end and projected along \(A\) with some velocity \(v\). The coefficient of friction between the block is \(\mu\). Then, the accelerations of blocks \(A\) and \(B\) before reaching a common velocity will be respectively
supporting img

1 \(\dfrac{\mu g}{2}\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
2 \(\mu g\) (towards right), \(\mu g\) (towards left)
3 \(\dfrac{\mu g}{2}\) (towards right), \(\mu g\) (towards left)
4 \(\mu g\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
PHXI05:LAWS OF MOTION

363348 Assertion :
The value of dynamic friction is less than the limiting friction.
Reason :
Once the motion has started, the inertia of rest has been overcome in case of friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI05:LAWS OF MOTION

363349 Statement A :
Kinetic friction always opposes the relative motion between the surfaces.
Statement B :
Static friction opposes or supports the motion.

1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
PHXI05:LAWS OF MOTION

363350 Find the maximum value of (\(M\)/\(m\)) in the situation shown in figure so that the system remains at rest. Friction coefficient of both the contacts is\(\mu \), string is massless and pulley is frictionless.
supporting img

1 \(\frac{{\sin \theta }}{{\sin \theta - \mu \cos \theta }}\)
2 \(\frac{{\cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
3 \(\frac{\mu }{{\sin \theta - \mu \cos \theta }}\)
4 \(\frac{{\mu \cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
PHXI05:LAWS OF MOTION

363351 If a block takes thrice as much time to slide down a \({\rm{45}}^\circ \) rough inclined plane as it takes to slide down a similar smooth plane. Then coefficient of friction is

1 \(\frac{1}{3}\)
2 \(\frac{2}{3}\)
3 \(\frac{9}{8}\)
4 \(\frac{8}{9}\)
PHXI05:LAWS OF MOTION

363347 A long block \(A\) of mass \(M\) is at rest on a smooth horizontal surface. A small block \(B\) of mass \(M / 2\) is placed on \(A\) at one end and projected along \(A\) with some velocity \(v\). The coefficient of friction between the block is \(\mu\). Then, the accelerations of blocks \(A\) and \(B\) before reaching a common velocity will be respectively
supporting img

1 \(\dfrac{\mu g}{2}\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
2 \(\mu g\) (towards right), \(\mu g\) (towards left)
3 \(\dfrac{\mu g}{2}\) (towards right), \(\mu g\) (towards left)
4 \(\mu g\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
PHXI05:LAWS OF MOTION

363348 Assertion :
The value of dynamic friction is less than the limiting friction.
Reason :
Once the motion has started, the inertia of rest has been overcome in case of friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI05:LAWS OF MOTION

363349 Statement A :
Kinetic friction always opposes the relative motion between the surfaces.
Statement B :
Static friction opposes or supports the motion.

1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
PHXI05:LAWS OF MOTION

363350 Find the maximum value of (\(M\)/\(m\)) in the situation shown in figure so that the system remains at rest. Friction coefficient of both the contacts is\(\mu \), string is massless and pulley is frictionless.
supporting img

1 \(\frac{{\sin \theta }}{{\sin \theta - \mu \cos \theta }}\)
2 \(\frac{{\cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
3 \(\frac{\mu }{{\sin \theta - \mu \cos \theta }}\)
4 \(\frac{{\mu \cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
PHXI05:LAWS OF MOTION

363351 If a block takes thrice as much time to slide down a \({\rm{45}}^\circ \) rough inclined plane as it takes to slide down a similar smooth plane. Then coefficient of friction is

1 \(\frac{1}{3}\)
2 \(\frac{2}{3}\)
3 \(\frac{9}{8}\)
4 \(\frac{8}{9}\)
PHXI05:LAWS OF MOTION

363347 A long block \(A\) of mass \(M\) is at rest on a smooth horizontal surface. A small block \(B\) of mass \(M / 2\) is placed on \(A\) at one end and projected along \(A\) with some velocity \(v\). The coefficient of friction between the block is \(\mu\). Then, the accelerations of blocks \(A\) and \(B\) before reaching a common velocity will be respectively
supporting img

1 \(\dfrac{\mu g}{2}\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
2 \(\mu g\) (towards right), \(\mu g\) (towards left)
3 \(\dfrac{\mu g}{2}\) (towards right), \(\mu g\) (towards left)
4 \(\mu g\) (towards right), \(\dfrac{\mu g}{2}\) (towards left)
PHXI05:LAWS OF MOTION

363348 Assertion :
The value of dynamic friction is less than the limiting friction.
Reason :
Once the motion has started, the inertia of rest has been overcome in case of friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI05:LAWS OF MOTION

363349 Statement A :
Kinetic friction always opposes the relative motion between the surfaces.
Statement B :
Static friction opposes or supports the motion.

1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
PHXI05:LAWS OF MOTION

363350 Find the maximum value of (\(M\)/\(m\)) in the situation shown in figure so that the system remains at rest. Friction coefficient of both the contacts is\(\mu \), string is massless and pulley is frictionless.
supporting img

1 \(\frac{{\sin \theta }}{{\sin \theta - \mu \cos \theta }}\)
2 \(\frac{{\cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
3 \(\frac{\mu }{{\sin \theta - \mu \cos \theta }}\)
4 \(\frac{{\mu \cos \theta }}{{\sin \theta - \mu \cos \theta }}\)
PHXI05:LAWS OF MOTION

363351 If a block takes thrice as much time to slide down a \({\rm{45}}^\circ \) rough inclined plane as it takes to slide down a similar smooth plane. Then coefficient of friction is

1 \(\frac{1}{3}\)
2 \(\frac{2}{3}\)
3 \(\frac{9}{8}\)
4 \(\frac{8}{9}\)