$300\, J$ of work is done in sliding a $2\, kg$ block up an inclined plane of height $10\, m.$ Work done against friction is.....$J$ (Take $g = 10 m/s^2)$

Explain the different forms of energy.

$(a)$ Heat Energy

$(b)$ Chemical Energy

$(c)$ Electrical Energy

A rocket accelerates straight up by ejecting gas downwards. In a small time interval $\Delta t$, it ejects a gas of mass $\Delta m$ at a relative speed $u$. Calculate $KE$ of the entire system at $t + \Delta t$ and $t$ and show that the device that ejects gas does work $=(\frac {1}{2})\Delta mu^2$ in this time interval (negative gravity).

A bolt of mass $0.3\; kg$ falls from the celling of an elevator moving down with an uniform speed of $7 \;m s ^{-1}$. It hits the floor of the elevator (length of the elevator $=3 \;m$ ) and does not rebound. What is the heat produced by the impact? Would your answer be different if the elevator were stationary?

A stone with weight $w$ is thrown vertically upward into the air from ground level with initial speed $v_0$. If a constant force $f$ due to air drag acts on the stone throughout its flight. The maximum height attained by the stone is

A wedge of mass $M = 4\,m$ lies on a frictionless plane. A particle of mass $m$ approaches the wedge with speed $v$. There is no friction between the particle and the plane or between the particle and the wedge. The maximum height climbed by the particle on the wedge is given by