A small bob tied at one end of a thin string of length 1 m is describing a vertical circle so that the maximum and minimum tension in the string are in the ratio 5:1. The velocity of the bob at the highest position is_________ m/s. (Take g=10m/s2)

At bottom, let say speed is v∴Tmax=mv2L+mgAs bob goes up, its speed decreases to uLoss in KE = Gain in PE⇒12mv2−12mu2=mg(2L)⇒u2=v2−4gL At top, tension is minimum, ⇒Tmin=mu2L−mg=mv2−4gLL−mg=mv2L−5mg Given :TmaxTmin=51⇒mv2L+mgmv2L−5mg=51⇒v2=132gL Thus, u2=v2−4gL=132gL−4gL=52gL⇒u=5×10×12=5m/s