A man standing near a well is supporting a bucket full of water with the help of a massless rope. The mass of bucket and water together is \(30~\text{kg}\). The length of the rope in the well is \(5~\text{m}\). The amount of work done in pulling the bucket up onto the top of the well is:  \(\left(\text{take }g= 9.8~\text{m/s}^2\right )\)
1. \(1470~\text{J}\)
2. \(1125~\text{J}\)
3. \(1062.5~\text{J}\)
4. \(562.5~\text{J}\)

Subtopic:  Gravitational Potential Energy |
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A cricket ball of mass \(0.15~\text{kg}\) is thrown vertically up by a bowling machine so that it rises to a maximum height of \(20~\text{m}\) after leaving the machine. If the part pushing the ball applies a constant force \(F\) on the ball and moves horizontally a distance of \(0.2~\text{m}\) while launching the ball, the value of \(F\) (in N) is: \((g=10~\text{m/s}^2) \)

1. \(50 ~\text{N} \) 2. \(100~\text{N} \)
3. \(150~\text{N} \) 4. \(200~\text{N} \)
Subtopic:  Gravitational Potential Energy |
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A uniform cable of mass \(M\) and length \(L\) is placed on a horizontal surface such that its \(\left ( \dfrac{1}{n} \right )^\text{th}\) part is hanging below the edge of the surface. To lift the hanging part of the cable up to the surface, the work done should be:

1. \(nMgl\) 2. \(\dfrac{MgL}{2n^2}\)
3. \(\dfrac{2MgL}{n^2}\) 4. \(\dfrac{4MgL}{n^2}\)
Subtopic:  Gravitational Potential Energy |
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A person trying to lose weight (dieter) lifts a \(10~\text{kg}\) mass, one thousand times, to a height of \(0.5~\text m\) each time. Assume that the potential energy lost each time she lowers the mass is dissipated. How much work does she do against the gravitational force?
1. \(29,000~\text J\)
2. \(49,000~\text J\)
3. \(21,000~\text J\)
4. \(18,000~\text J\)

Subtopic:  Gravitational Potential Energy |
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