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The equation of a wave on a string of linear mass density 0.04 kg m⁻¹ is given by y = 0.02(m) sin [2π ( t/(0.04(s)) − x/(0.50(m)))]. The tension in the string is

1. 4.0 N
2. 12.5 N
3. 0.5 N
4. 6.25 N

Correct answer: 6.25 N

Solution

From y = 0.02 sin[2pi(t/0.04 - x/0.50)], wave speed v = lambda/T = 0.50/0.04 = 12.5 m/s. Tension T = mu*v^2 = 0.04 * 12.5^2 = 6.25 N.

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