Work Energy and...

A block is acted upon by a force, which is inversely proportional to the displacement $$x$$. The work done will be proportional to

The hydroelectric plants do not produce electricity, if the water level in the dam is less than 34 m.

A small sphere is attached to a cord and rotates in a vertical circle about a point $$O$$. If the average speed of the sphere is increased, the cord is most likely to break at the orientation when the mass is at

During the displacement, which of the curves shown in the graph best represents the work done on the spring block system by the applied force ?

A body starts from rest and acquires a velocity $$V$$ in time $$T$$ at constant rate. The work done on the body in time $$t$$ will be proportional to

A bob is suspended from a crane by a cable of length $$5m$$. The crane and load are moving at a constant speed $$v_{0}$$. The crane is stopped by a bumper and the bob on the cable swings out an angle of $$60^{\circ}$$. Find the initial speed $$v_{0}.(g=9.8 m/s^{2})$$

A simple pendulum is vibrating with angular amplitude of $$\theta=90^{o}$$ as shown in figure.
For what value of $$\theta$$ is the acceleration directed
$$(i)$$ Vertically upwards
$$(ii)$$ Horizontally
$$(iii)$$ Vertically downwards

A force $$\displaystyle \vec{F}= \left ( 3t\hat{i}+5\hat{j} \right )N$$ acts on a body due to which its displacement varies as $$\displaystyle \vec{S}= \left ( 2t^{2}\hat{i}-5\hat{j} \right )m.$$ Work done by this force in 2 second is:

A stone tied to a string of length $$L$$ is swired in a verticle circle with the other end of the string at the centre. At a certain instant of time the stone is at it lowest position and has a speed $$u$$. Find the magnitude of the change in its velocity as it reaches a position, where the string is horizontal.