Mass of rocket is greater than mass of gases as the rocket is used for carrying a satellite etc. to a suitable height above the ground.

The first cell was observed in cork slice. Robert Hooke in 1665, observed the cells in a cork slice with the help of a primitive microscope.

Farmers typically use techniques such as hand picking, breaking and sifting to purify the grain.

Separation of components of a mixture is done to obtain purity of a substance and remove undesirable components.

According to Newton’s second law of motion. Force = Rate of change in momentum F = m(v-u)/t = 5 (12 – 8)/4 = 5 N