高中物理问题（题目是英文）要详细过程

A gun of mass 5.00 tonne fires a shot of mass 23kg horizontally and recoils 1.50m. The recoil is resisted by a constant force of 10.0 kN. Calculate the muzzle velocity of the shot (i.e. the speed of the shot as it emerges from the gun).

A man of mass 70kg stands at the end of a rough wooden plank of mass 35kg and length 9m. The plank is situated on a smooth table. The man walks from one end of the plank to the other.

(a)How far does the man walk relative to the table?

(b)How far does the plank slip back?

(c)How far has the centre of mass of the system (man+plank) moved?

A particle of mass m strikes a wall at right angles with speed v and rebounds at the same speed

(a)What impulse is exerted on the wall by the collision?

(b)If n particles rebound in this way per second, what is the average force exerted by the particles on the wall?

A bullet of mass 6.00×10^-3 kg is fired horizontally into a block of wood that rests on a horizontal table. After the collision an opposing force of 1.50N brings the block, with embedded bullet, to rest in 2.00s

Find the speed of the bullet just before it struck the block

A gun of mass 5.00t fires a shot of mass 20.0kg and recoils 2.00m along the line of projection against an opposing force of 1.00×10^4N.

Calculate the velocity with which the shot leaves the gun.