Force acting on a particle is $\left(2\hat{\mathrm{i}}+3\hat{\mathrm{j}}\right) \mathrm{N}$. Work done by this force is zero, when a particle is moved on the line $3y+kx=5$. The value of $k$ is

A block of mass $m$ is sliding down an inclined plane with constant speed. At a certain instant $t_0,$ its height above the ground is $h.$ The coefficient of kinetic friction between the block and the the plane is $\mu .$ If the block reaches the ground at a later instant $t_g,$ then the energy dissipated by friction in the time interval $\left(t_{\mathrm{g}}-t_0\right)$ is,