In the figure below, two identical metal balls A and B having equal masses are being dropped towards the surface of moon and earth. Analyse the given data and answer the following questions:

1. If both the metal balls are released simultaneously, which one does strike the ground faster? Show with calculation.
2. A person lifts 30kg on the surface of the earth. How much mass can he lift on the surface of the moon if he applies same magnitude of force?

1. In case of the moon :-
   
   Given
   
   Distance, s = 10 m
   
   Acceleration, a = 1.62 m/s²
   
   Initial velocity, u = 0
   
   Time, t = ?
   
   S = u t + ½ a t²
   
   10 m = 0 × t + ½ × 1.62 m/s² × t²
   
   10 m = 0.81 m/s² × t²
   
   t² = 10 / 0.81 s² = 12.346 s²
   
   ∴ t =3.514 s
   
   
   In case of the Earth :-
   
   Given
   
   Distance, s = 10 m
   
   Acceleration, a = 9.8 m/s²
   
   Initial velocity, u = 0
   
   Time, t = ?
   
   S = u t + ½ a t²
   
   10 m = 0 × t + ½ × 9.8 m/s² × t²
   
   10 m = 4.9 m/s² × t²
   
   t² = 10 / 4.9 s² = 2.041 s²
   
   ∴ t =1.429 s
   
   Here from the above calculations it is seen that time in case of the Earth is smaller than in case of the moon. So, the ball falling on the Earth will strike the ground faster.



2. Given
   
   Mass of the ball, m = 30 Kg
   
   Acceleration due to gravity at the earth surface, g = 9.8 m/s²
   
   Force applied, F = m.g = 30 kg × 9.8 m/s² = 294 N.
   
   On the moon :-
   
   Acceleration due to gravity at the earth surface, g = 1.62 m/s²
   
   Force applied, F = 294 N
   
   Mass that can be lifted on the surface of the moon = 294/1.62 Kg = 181.481 Kg
   
   181.481 Kg mass can he lift on the surface of the moon if he applies same magnitude of force as on the Earth's surface.