The energy stored in a wound watch spring is:

In the figure shown,the potential energy $(U)$ of a particle is plotted against its position $x$ from the origin. The particle at:

In the equation $W = -mgh$,what does the negative sign indicate?

$A$ particle is placed at the origin and a force $F = kx$ is acting on it (where $k$ is a positive constant). If $U(0) = 0$,the graph of $U(x)$ versus $x$ will be (where $U$ is the potential energy function):

$A$ rod of length $4 \ m$ and mass $20 \ kg$ is lying horizontally on the ground. Calculate the work done in $J$ to keep it in a vertical position such that one end remains in contact with the ground.

The potential energy of a particle oscillating along the $x-$axis is given by $U = 20 + (x - 2)^2$,where $U$ is in joules and $x$ is in meters. The total mechanical energy of the particle is $36\,J$. The maximum kinetic energy of the particle is ................ $J$.