Torque applied is maximum when the angle between the directions of $\overrightarrow{r}\backslash overrightarrow\; r$ and $\overrightarrow{F}\backslash overrightarrow\; F$ is

A force F = 20 + 10y acts on a particle in ydirection where F is in newton and y in meter. Work done by this force to move the particle from y = 0 to y = 1 m is:

Body A of mass 4m moving with speed u collides with another body B of mass 2m, at rest. The collision is head on and elastic in nature. After the collision the fraction of energy lost by the colliding body A is:

The centre of mass of two particles system lies

A moving block having mass m, collides with another stationary block having mass 4m. The lighter block comes to rest after collision, When the initial velocity of the lighter block is v, then the value of coefficient of restitution (e) will

In a collinear collision, a particle with an initial speed $v_{0}v\_0$ strikes a stationary particle of the same mass. If the final total kinetic energy is 50% greater than the original kinetic energy, the magnitude of the relative velocity between the two particles, after collision, is:

A bomb at rest explodes into 3 parts of same mass. The momentum of two parts is -3P $\widehat{i}\backslash hat\; i$ and 2P$\widehat{j}\backslash hat\; j$ respectively. The magnitude of momentum of the third part is

A sphere of mass ‘m’ moving with velocity V collides head-on on another sphere of same mass which is at rest. The ratio of final velocity of second sphere to the initial velocity of the first sphere is (e is coefficient of restitution and collision is inelastic)

A time dependent force F = 6t acts on a particle of mass 1 kg. If the particle starts from rest, the work done by the force during the first 1 sec. will be

A passenger in a moving bus is thrown forward when the bus is suddenly stopped. This is explained