A spherical ball of radius 1 10⁻⁴ ~m and of density 104 kg m ⁻³ falls freely under gravity through a distance ' h ' before entering a tank of water. After' entering water if the velocity of the ball does not change, then ' h ' is

Step-by-step solution

r =1 10⁻⁴ ~m , =10^4 ~kg ~m ⁻³ Terminal speed, v= 2 9 gr ^2 ( - ) aligned & = 2 9 9.8 (10⁻⁴ )^2 9.8 10⁻⁶ (10^4-10^3 ) & =20 ~m / s aligned By conservation of mechanical energy, aligned & 1 2 mv ^2= mgh & ~h = v ^2 2 ~g = (20)^2 2 9.8 =20.4 ~m aligned