Define $SI$ unit of force $N$. Define $CGS$ unit of force dyne.

A pebble of mass $0.05\; kg$ is thrown vertically upwards. Give the direction and magnitude of the net force on the pebble,

$(a)$ during its upward motion,

$(b)$ during its downward motion,

$(c)$ at the highest point where it is momentarily at rest.

Do your answers change if the pebble was thrown at an angle of $45^o$ with the horizontal direction? Ignore air resistance.

The horizontal acceleration that should be given to a smooth inclined plane of angle $sin^{-1}\, (1/l)$ to keep an object stationary on the plane relative to the inclined plane is

Two masses $m$ and $M$ are attached to the strings as shown in the figure. If the system is in equilibrium, then 

At the instant $t = 0$ a force $F = kt$ ( $k$ is a constant) acts on a small body of mass $m$ resting on a smooth horizontal surface. The time, when body leaves the surface is

A small child tries to move a large rubber toy placed on the ground. The toy does not move but gets deformed under her pushing force $F$, which is obliquely upward as shown in the figure.Then,