In an experiment, a small steel ball falls through a liquid at a constant speed of 10 ~cm / s . If the steel ball is pulled upward with a force equal to twice its effective weight, how fast will it move upward ?

Step-by-step solution

Weight of the body W = mg = 4 3 r ^3 g T = 4 3 r ^3 g and F =6 vr When the body attains terminal velocity net force acting on the body is zero. i.e., W - T - F =0 And terminal velocity v = 2 9 r ^2( - ) g As in case of upward motion upward force is twice its effective weight, therefore, it will move with same speed 10 ~cm / s