Question

A wooden stick 2m long is floating on the surface of water. The surface tension of water 0.07 N/m. By putting soap solution on one side of the sticks the surface tension is reduced to 0.06 N/m. The net force on the stick will be

• A. 0.07 N
• B. 0.06 N
• C. 0.01 N
• D. 0.02 N

Answer 1

Answer: (D)

0.02 N

Answer 2

Force on one side of the stick $F _ { 1 } = T _ { 1 } \times L$

$= 0.07 \times 2 = 0.14 N$

and force on other side of the stick $F _ { 2 } = T _ { 2 } \times L$

So net force on the stick $= F _ { 1 } - F _ { 2 } = 0.14 - 0.12 = 0.02 \mathrm {~N}$