A particle is kept at rest at a distance R (earth's radius) above the earth's surface, the minimum speed with which it should projected so that it does not return is ____________.

When a projectile is at its maximum height, the direction of its velocity and acceleration are _____________.

The angle between the normal force and the resultant force of normal force and maximum frictional force is _____________.

In a rectangle ABCD (BC = 2AB). The moment of inertia is minimum along axis through _____________
 

An escalator is moving downwards with a uniform speed 5 ms^-1. A man of mass 60 kg is running upwards on it at a uniform speed 10 ms^-1. If the height of the escalator is 10 m, the work done by the man is going up the escalator is ____________. (Take g = 10 ms^-2).

A person holding a rifle (mass of person and rifle together is 100 kg) stands on a smooth surface and fires 10 shots horizontally, in 5 s. Each bullet has a mass of 10 g with a muzzle velocity of 800 ms^-1. The final velocity acquired by the person and the average force exerted on the person are ________________.

The speed of a train is reduced from 60 kmh^-1 to 15 kmh^-1 in a distance of 450 m. If the retardation is uniform is the distance, it will travel further before coming to rest is _______________.

A marble block of mass 3 kg lying on ice when given a velocity of 5 ms^-1 is stopped by friction in 10s. Then the coefficient of friction is ______________.

When a mass is rotating in a plane about a fixed point its angular momentum is directed along ______________.

Microscopic group of Physics dealt with the study of ____________.