A pendulum bob has a speed of 3 m/s at its lowest position. The pendulum is 0.5 m long. The speed of the bob, when the length makes an angle of 60o to the vertical, will be (If  g=10m/s2 )

Let bob velocity be v at point B where it makes an angle of 60o with the vertical, then using conservation of mechanical energyKEA+PEA=KEB+PEB⇒12m×32=12mv2+mgl(1−cosθ)⇒9=v2+2×10×0.5×12⇒v=2m/s