A man of 100kg starts to move on the earth (mass 6.4x10kg), and acquires a speed of 3m/s. With what speed does the earth recoil?
Solution. (Hint: Momentum is conserved in the process)

-4.6875 m/s

Explanation:

Mass of man; m_m = 100 kg

Mass of earth; m_e = 6.4 × 10 kg = 64 kg

Speed of man; v_m = 3 m/s

Since we are told that momentum is conserved, it means that momentum of the man will be equal and opposite to momentum of the Earth.

Thus;

m_m × v_m = -m_e × v_e

100 × 3 = -64 × v_e

v_e = 300/-64

v_e = -4.6875 m/s

the answer is false. this is because for ice to melt, it requires latent heat of melting. latent heat means heat energy required to change phase without any increase in temperatures. therefore, the ice will take energy from the environment to melt hence atmospheric temperatures will reduce.