Find the loss of mechanical energy when a body is projected up the inclined plane inclined at angle@ and with velocity V

What is the repulsive force between two pith balls that are 8 cm apart and have equal charges of -30 nC?

If the time of flight of a projectile is 10 secinds, range is 500 metres. Then what is the maximum height attained by it?

A 75.0 g bullet is fired at a muzzle velocity of 476 m/s from a gun with a mass 4.75 kg and a barrel length of 60 cm How long is the bullet in the barrel?

A roller coaster moves 85 m horizontally, then travels 45 m at an angle of 30 degrees above horizontal. What is the displacement from its starting point?