Question

As shown in figure string PQR is stretched by force F = (3 –10 Kt) N, where k is a constant and t is time in second. At time t = 0, a pulse is generated at the end P of the string. Find the value of K (in N/s) if the value of force become zero as the pulse reaches point Q.(linear density of string is $3\times {10}^{-2}kg{m}^{-1}$)

Answer 1

$v=\sqrt{\frac{3-\left(10K\right)t}{3\times {10}^{-2}}}=\frac{dx}{dt}{\int }_0^{L}dx=\frac{10}{\sqrt{3}}{\int }_0^t\sqrt{3-10kt}.dt$
answer:2