Work
PHXI06:WORK ENERGY AND POWER

355851 A block of mass \(m\) moving with a velocity \(v_{0}\) on a smooth horizontal surface strikes and compresses a spring of stiffiness \(k\) till mass comes to rest as shown in the figure. This phenomenon is observed by two observers:
\(A\): Standing on the horizontal surface
\(B\): Standing on the block W.r.to the observer \(A\), the work done by spring force is:
supporting img

1 \(-\dfrac{1}{2} m v_{0}^{2}\)
2 Negative but nothing can be said about its magnitude
3 Positive but nothing can be said about its magnitude
4 \(+\dfrac{1}{2} m v_{0}^{2}\)
PHXI06:WORK ENERGY AND POWER

355852 A block of mass \(m\) is suspended by a light thread from an elevator. The elevator is accelerating upward with uniform acceleration \(a\). The work done by tension on the block during \(\mathrm{t}\) seconds from the ground frame and the lift frame are:
supporting img

1 \(\dfrac{m}{2}(g+a) a t^{2}, 0\)
2 \(\dfrac{m}{2}(g-a) a t^{2}, \dfrac{m}{2}(g+a) a t^{2}\)
3 \(\frac{m}{2}g\,a{t^2},0\)
4 0,0
PHXI06:WORK ENERGY AND POWER

355853 A block of mass \(m\) is lying at rest at point \(P\) of a wedge having a smooth semi-circular track of radius \(R\). What should be the minimum value of \(a_{0}\) so that the mass can just reach point \(Q\) ?
supporting img

1 \(\dfrac{g}{2}\)
2 \(\sqrt{g}\)
3 \(g\)
4 Not possible
PHXI06:WORK ENERGY AND POWER

355854 Consider two observers moving with respect to each other at a speed \(v\) along a straight line. They observe a block of mass m moving a distance \(l\) on a rough surface. The following quantity will be same as observed by the observers

1 Total work done on the block
2 Acceleration of the block
3 Work done by friction
4 Kinetic energy of the block at time \(t\)
PHXI06:WORK ENERGY AND POWER

355855 One end of a spring of force constant \(k_{1}\) is attached to the ceiling of an elevator. A block of mass 1.5 \(kg\) is attached to the other end. Another spring of force constant \(k_{2}\) is attached to the bottom of the mass and to the floor of the elevator as shown in figure. At equilibrium, the deformation in both the springs is equal and is 40 \(cm\) . If the elevator moves with constant acceleration upward,the additional deformation in both the spring is 8 \(cm\) . Find the elevator's acceleration \((g = 10\,\,m{s^{ - 2}})\).
supporting img

1 \(5\,m{s^{ - 2}}\)
2 \(1\,m{s^{ - 2}}\)
3 \(8\,m{s^{ - 2}}\)
4 \(2\,m{s^{ - 2}}\)
PHXI06:WORK ENERGY AND POWER

355851 A block of mass \(m\) moving with a velocity \(v_{0}\) on a smooth horizontal surface strikes and compresses a spring of stiffiness \(k\) till mass comes to rest as shown in the figure. This phenomenon is observed by two observers:
\(A\): Standing on the horizontal surface
\(B\): Standing on the block W.r.to the observer \(A\), the work done by spring force is:
supporting img

1 \(-\dfrac{1}{2} m v_{0}^{2}\)
2 Negative but nothing can be said about its magnitude
3 Positive but nothing can be said about its magnitude
4 \(+\dfrac{1}{2} m v_{0}^{2}\)
PHXI06:WORK ENERGY AND POWER

355852 A block of mass \(m\) is suspended by a light thread from an elevator. The elevator is accelerating upward with uniform acceleration \(a\). The work done by tension on the block during \(\mathrm{t}\) seconds from the ground frame and the lift frame are:
supporting img

1 \(\dfrac{m}{2}(g+a) a t^{2}, 0\)
2 \(\dfrac{m}{2}(g-a) a t^{2}, \dfrac{m}{2}(g+a) a t^{2}\)
3 \(\frac{m}{2}g\,a{t^2},0\)
4 0,0
PHXI06:WORK ENERGY AND POWER

355853 A block of mass \(m\) is lying at rest at point \(P\) of a wedge having a smooth semi-circular track of radius \(R\). What should be the minimum value of \(a_{0}\) so that the mass can just reach point \(Q\) ?
supporting img

1 \(\dfrac{g}{2}\)
2 \(\sqrt{g}\)
3 \(g\)
4 Not possible
PHXI06:WORK ENERGY AND POWER

355854 Consider two observers moving with respect to each other at a speed \(v\) along a straight line. They observe a block of mass m moving a distance \(l\) on a rough surface. The following quantity will be same as observed by the observers

1 Total work done on the block
2 Acceleration of the block
3 Work done by friction
4 Kinetic energy of the block at time \(t\)
PHXI06:WORK ENERGY AND POWER

355855 One end of a spring of force constant \(k_{1}\) is attached to the ceiling of an elevator. A block of mass 1.5 \(kg\) is attached to the other end. Another spring of force constant \(k_{2}\) is attached to the bottom of the mass and to the floor of the elevator as shown in figure. At equilibrium, the deformation in both the springs is equal and is 40 \(cm\) . If the elevator moves with constant acceleration upward,the additional deformation in both the spring is 8 \(cm\) . Find the elevator's acceleration \((g = 10\,\,m{s^{ - 2}})\).
supporting img

1 \(5\,m{s^{ - 2}}\)
2 \(1\,m{s^{ - 2}}\)
3 \(8\,m{s^{ - 2}}\)
4 \(2\,m{s^{ - 2}}\)
PHXI06:WORK ENERGY AND POWER

355851 A block of mass \(m\) moving with a velocity \(v_{0}\) on a smooth horizontal surface strikes and compresses a spring of stiffiness \(k\) till mass comes to rest as shown in the figure. This phenomenon is observed by two observers:
\(A\): Standing on the horizontal surface
\(B\): Standing on the block W.r.to the observer \(A\), the work done by spring force is:
supporting img

1 \(-\dfrac{1}{2} m v_{0}^{2}\)
2 Negative but nothing can be said about its magnitude
3 Positive but nothing can be said about its magnitude
4 \(+\dfrac{1}{2} m v_{0}^{2}\)
PHXI06:WORK ENERGY AND POWER

355852 A block of mass \(m\) is suspended by a light thread from an elevator. The elevator is accelerating upward with uniform acceleration \(a\). The work done by tension on the block during \(\mathrm{t}\) seconds from the ground frame and the lift frame are:
supporting img

1 \(\dfrac{m}{2}(g+a) a t^{2}, 0\)
2 \(\dfrac{m}{2}(g-a) a t^{2}, \dfrac{m}{2}(g+a) a t^{2}\)
3 \(\frac{m}{2}g\,a{t^2},0\)
4 0,0
PHXI06:WORK ENERGY AND POWER

355853 A block of mass \(m\) is lying at rest at point \(P\) of a wedge having a smooth semi-circular track of radius \(R\). What should be the minimum value of \(a_{0}\) so that the mass can just reach point \(Q\) ?
supporting img

1 \(\dfrac{g}{2}\)
2 \(\sqrt{g}\)
3 \(g\)
4 Not possible
PHXI06:WORK ENERGY AND POWER

355854 Consider two observers moving with respect to each other at a speed \(v\) along a straight line. They observe a block of mass m moving a distance \(l\) on a rough surface. The following quantity will be same as observed by the observers

1 Total work done on the block
2 Acceleration of the block
3 Work done by friction
4 Kinetic energy of the block at time \(t\)
PHXI06:WORK ENERGY AND POWER

355855 One end of a spring of force constant \(k_{1}\) is attached to the ceiling of an elevator. A block of mass 1.5 \(kg\) is attached to the other end. Another spring of force constant \(k_{2}\) is attached to the bottom of the mass and to the floor of the elevator as shown in figure. At equilibrium, the deformation in both the springs is equal and is 40 \(cm\) . If the elevator moves with constant acceleration upward,the additional deformation in both the spring is 8 \(cm\) . Find the elevator's acceleration \((g = 10\,\,m{s^{ - 2}})\).
supporting img

1 \(5\,m{s^{ - 2}}\)
2 \(1\,m{s^{ - 2}}\)
3 \(8\,m{s^{ - 2}}\)
4 \(2\,m{s^{ - 2}}\)
PHXI06:WORK ENERGY AND POWER

355851 A block of mass \(m\) moving with a velocity \(v_{0}\) on a smooth horizontal surface strikes and compresses a spring of stiffiness \(k\) till mass comes to rest as shown in the figure. This phenomenon is observed by two observers:
\(A\): Standing on the horizontal surface
\(B\): Standing on the block W.r.to the observer \(A\), the work done by spring force is:
supporting img

1 \(-\dfrac{1}{2} m v_{0}^{2}\)
2 Negative but nothing can be said about its magnitude
3 Positive but nothing can be said about its magnitude
4 \(+\dfrac{1}{2} m v_{0}^{2}\)
PHXI06:WORK ENERGY AND POWER

355852 A block of mass \(m\) is suspended by a light thread from an elevator. The elevator is accelerating upward with uniform acceleration \(a\). The work done by tension on the block during \(\mathrm{t}\) seconds from the ground frame and the lift frame are:
supporting img

1 \(\dfrac{m}{2}(g+a) a t^{2}, 0\)
2 \(\dfrac{m}{2}(g-a) a t^{2}, \dfrac{m}{2}(g+a) a t^{2}\)
3 \(\frac{m}{2}g\,a{t^2},0\)
4 0,0
PHXI06:WORK ENERGY AND POWER

355853 A block of mass \(m\) is lying at rest at point \(P\) of a wedge having a smooth semi-circular track of radius \(R\). What should be the minimum value of \(a_{0}\) so that the mass can just reach point \(Q\) ?
supporting img

1 \(\dfrac{g}{2}\)
2 \(\sqrt{g}\)
3 \(g\)
4 Not possible
PHXI06:WORK ENERGY AND POWER

355854 Consider two observers moving with respect to each other at a speed \(v\) along a straight line. They observe a block of mass m moving a distance \(l\) on a rough surface. The following quantity will be same as observed by the observers

1 Total work done on the block
2 Acceleration of the block
3 Work done by friction
4 Kinetic energy of the block at time \(t\)
PHXI06:WORK ENERGY AND POWER

355855 One end of a spring of force constant \(k_{1}\) is attached to the ceiling of an elevator. A block of mass 1.5 \(kg\) is attached to the other end. Another spring of force constant \(k_{2}\) is attached to the bottom of the mass and to the floor of the elevator as shown in figure. At equilibrium, the deformation in both the springs is equal and is 40 \(cm\) . If the elevator moves with constant acceleration upward,the additional deformation in both the spring is 8 \(cm\) . Find the elevator's acceleration \((g = 10\,\,m{s^{ - 2}})\).
supporting img

1 \(5\,m{s^{ - 2}}\)
2 \(1\,m{s^{ - 2}}\)
3 \(8\,m{s^{ - 2}}\)
4 \(2\,m{s^{ - 2}}\)
PHXI06:WORK ENERGY AND POWER

355851 A block of mass \(m\) moving with a velocity \(v_{0}\) on a smooth horizontal surface strikes and compresses a spring of stiffiness \(k\) till mass comes to rest as shown in the figure. This phenomenon is observed by two observers:
\(A\): Standing on the horizontal surface
\(B\): Standing on the block W.r.to the observer \(A\), the work done by spring force is:
supporting img

1 \(-\dfrac{1}{2} m v_{0}^{2}\)
2 Negative but nothing can be said about its magnitude
3 Positive but nothing can be said about its magnitude
4 \(+\dfrac{1}{2} m v_{0}^{2}\)
PHXI06:WORK ENERGY AND POWER

355852 A block of mass \(m\) is suspended by a light thread from an elevator. The elevator is accelerating upward with uniform acceleration \(a\). The work done by tension on the block during \(\mathrm{t}\) seconds from the ground frame and the lift frame are:
supporting img

1 \(\dfrac{m}{2}(g+a) a t^{2}, 0\)
2 \(\dfrac{m}{2}(g-a) a t^{2}, \dfrac{m}{2}(g+a) a t^{2}\)
3 \(\frac{m}{2}g\,a{t^2},0\)
4 0,0
PHXI06:WORK ENERGY AND POWER

355853 A block of mass \(m\) is lying at rest at point \(P\) of a wedge having a smooth semi-circular track of radius \(R\). What should be the minimum value of \(a_{0}\) so that the mass can just reach point \(Q\) ?
supporting img

1 \(\dfrac{g}{2}\)
2 \(\sqrt{g}\)
3 \(g\)
4 Not possible
PHXI06:WORK ENERGY AND POWER

355854 Consider two observers moving with respect to each other at a speed \(v\) along a straight line. They observe a block of mass m moving a distance \(l\) on a rough surface. The following quantity will be same as observed by the observers

1 Total work done on the block
2 Acceleration of the block
3 Work done by friction
4 Kinetic energy of the block at time \(t\)
PHXI06:WORK ENERGY AND POWER

355855 One end of a spring of force constant \(k_{1}\) is attached to the ceiling of an elevator. A block of mass 1.5 \(kg\) is attached to the other end. Another spring of force constant \(k_{2}\) is attached to the bottom of the mass and to the floor of the elevator as shown in figure. At equilibrium, the deformation in both the springs is equal and is 40 \(cm\) . If the elevator moves with constant acceleration upward,the additional deformation in both the spring is 8 \(cm\) . Find the elevator's acceleration \((g = 10\,\,m{s^{ - 2}})\).
supporting img

1 \(5\,m{s^{ - 2}}\)
2 \(1\,m{s^{ - 2}}\)
3 \(8\,m{s^{ - 2}}\)
4 \(2\,m{s^{ - 2}}\)