a rifle of mass 6.2 kilograms recoils at a speed of 221 m/s after firing a 150 gram bullet. with what speed does the bullet fire with

At maximum height, kinetic energy is converted in potential energy  formula: at max height, ke = ½ * 0.27kg * (16m/s) ² = 34.56 j  so the remaining pe = (41.70 – 34.56)= 7.14 j = 0.27 kg * 9.8m/s² * h  = (9.8/7.14 * 0.27)so max height h = 5.08 or 5 m 

Phagocytes contain digestive enzymes to facilitate the process of phagocytosis

You need to calculate the string in between two masses