When a, bullet leave a gun, the gun presses on the shoulder of the person firing the gun. Explain why.

A fighter plane flying horizontally at an altitude of .1.5 km with speed 720 km/h passes directly overhead an anti-aircraft gun. At what angle from the vertical should the gun be fired for the shell with muzzle speed 600 m s^-1 to hit the plane? At what minimum altitude should the pilot fly the plane to avoid being hit? (Take g = 10 m s^-2) .

A man’stationed between two hills fires a gun. He hears the first echo after 1 s and the second after 2 s. What is the distance between the hills. The speed of sound in air is 330 m/s.

When HCI reacts with finely powdered iron, it forms ferrous chloride and not ferric chloride. Explain, Why?

Explain why When we try to close a watertap with our fingers, fast jets of water gush through the openings between our fingers

Why does a gun recoil when a bullet is fixed.

Define impulse. A machine gun of 10kg mass fires 25 gm bullets at the rate of 5 bullets per second with a speed of 500 ms^(-1) . What force must be applied to the gun to hold it in position.

Explain when small pieces of ice pressed together, form a single block.

Explain why: n optical pyrometer (for measuring high temperatures) calibrated for an ideal black body radiation gives too low a value for the temperature of a red hot iron piece in the open, but gives a correct value for the temperature when the same piece is in the furnace