Aa stone of mass 1 kg is tied with a string and it is whirled in a vertical circle of radius 1 m. If tension at the highest point is 14 N, then velocity at lowest point will be:-

a) 3 m/s
b) 4 m/s
c) 6 m/s
d) 8 m/s

The tension at the top is given byT=mvt2r-mgor, 14=1×vt21-1×10=vt2-10 (taking g=10)or, vt2=4or, vt=2Now loss of potential energy at the bottom is Kp=mgh=1×10×2=20So total kinetic energy at the bottom is 12mvb2=20+12mvt2=20+2=22so vb=44=6.6So answer c) is correct. 

  • -187
What are you looking for?