InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
A block of mass M is hanging over a smooth and light pulley through a light string. The other end of the string is pulled by a constant force F. The kinetic energy of the block increases by 20 J in 1 s.(a) The tension in the string is Mg.(b) The tension in the string is F.(c) The work done by the tension on the block is 20 J in the above 1 s.(d) The work done by the force of gravity is —20 J in the above 1 s. |
|
Answer» (b) The tension in the string is F. Explanation: (a) is not true because if the tension in the string is Mg the block cant be pulled up. It can only happen when the tension in the string is F. So (b) is true. Since K.E. of the block increases by 20J, it means work done by the resultant force on the block is 20 J. But neither the tension nor the force of gravity is the resultant force on the block. Hence (c) and (d) are not true. |
|