21. A stone of mass 1 kg is tied with a string and it is whirled in a vertical circle of radius 1 m. If tension at the highest point is 14 N, then velocity at the lowest point will be?
- 3 m/s
- 4 m/s
- 6 m/s
- 8 m/s
22. A string is used to pull a block of mass ‘m’ vertically up by a distance ‘h’ at a constant acceleration ‘g/3’. The work done by the tension in the string is?
23. A particle moves along X-axis from x = 0 to x = 1 m under the influence of a force given by F = 3x² + 2x – 10 . Work done in the process is?
24. A man carries a load on his head through a distance of 5 m. The maximum amount of work is done when he
- moves it over an inclined plane
- moves it over a horizontal surface
- lifts it vertically upwards
- None of these
25. If 250 J of work is done by sliding a 5 kg block up an inclined plane of height 4 m. Work done against friction is (g = 10 m/s²)?
- 100 J
- 50 J
- 150 J