Question

A massless container is filled with liquid of density r. It contains two holes as shown in figure. Container rests on ground. Area of the two holes are A each. Container is filled with liquid upto height H. Then –

• A. Torque produced by normal force between container & ground about center of gravity is $\frac{\rho AgH^{2}}{2}$ into the plane of paper
• B. Torque produced by friction about center of gravity is rAgH² out of the plane of paper
• C. Net torque produce by thrust force & friction force about center of gravity is $\frac{\rho AgH^{2}}{4}$ into the plane of paper
• D. Torque produced by normal force between container and ground about centre of gravity is zero

Answer 1

Answer: (D)

Torque produced by normal force between container and ground about centre of gravity is zero

Answer 2

Net force acting on container due to liquid coming out from the holes is given by

F = rA $\left\lbrack 2g \times \frac{3H}{4} - 2g \times \frac{H}{4} \right\rbrack$ = rgAH towads left

\ F = f = rgAH towards right.

Now, t_F = rgAH × $\frac{H}{2}$ into the plane of paper.

t_f = rgAH × $\frac{H}{2}$ out of plane of papers

\ t_F = t_f hence t_N = 0