Question
A man generates a symmetrical pulse in a string by moving his hand up and down. At t=0 the point in his hand moves downward from mean positoon. The pulse travels with speed of 3 m/s on the string and his hand passes 6 times in each second from the mean position. Then the point on the string at a distance 3 m will reach its upper extreme first time at time t=n/12. Then find n?