Question

A matchstick 5 cm long floats on water. The water film has a surface tension of 70 dyne/cm. A little camphor put on one side of the stick reduces the surface tension there to 50 dyne/cm. The net force on the matchstick is

Answer 1

A matchstick 5 cm long floats on water. The water film has a surface tension of 70 dyne/cm. A little camphor put on one side of the stick reduces the surface tension there to 50 dyne/cm.

we have to find the net force on the matchstick.

One side of the matchstick acting F₁ force and F₂ is the force acting on other side of it.

so, net force on the matchstick, F = F₁ - F₂

[ ∵ both forces are in opposite directions ]

surface is the force per unit length.

i.e., F = T × L

so, F₁ = T₁ × L

= 70 Dyne/cm × 5cm

= 350 Dyne

similarly, F₂ = T₂ × L

= 50 Dyne/cm × 5cm

= 250 Dyne

now net force, F = 350 - 250 = 100 Dyne

Therefore the net force on the matchstick is 100 Dyne.

Answer 2

Hey man when @Abhi178 have given the answer then why are you expecting more better answer than him.

If you are expecting that then you have to go to his place for some sort of Physics Quiz