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Question
A 5.0 cm long straight piece of thread is kept on the surface of water. Find the force with which the surface on one side of the thread pulls it. Surface tension of water = 0.076 N m−1.
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Solution
Given:
Length of thread l = 5 cm = 5 × 10−2 m
Surface tension of water T = 0.76 N/m
We know that:
F = T × l = 0.76 × 5 × 10−2
= 3.8 × 10−3 N
Therefore, the water surface on one side of the thread pulls it with a force of 3.8 × 10−3N
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