A matchstick 5 cm long floats on water. The water film has a surface tension of 70 dyn/cm. A little comphor put on one side of stick reduces the surface tension there to 50 dyn/cm. The net force on the matchstick is
A. 4 dynes
B. 20 dynes
C. 100 dynes
D. 600 dynes.
Answer:C
A matchstick 5 cm long floats on water. The water film has a surface tension of 70 dyn/cm. A little comphor put on one side of stick reduces the surface tension there to 50 dyn/cm. The net force on the matchstick is
A. 4 dynes B. 20 dynes C. 100 dynes D. 600 dynes.