Question

A particle suspended from a fixed point by a light inextensible side of length l is projected horizontally from its lowest position with velocity root 7gl divided by 2 the thread was like after swinging through an angle such

Answer 1

hope you will understand

Answer 2

The angle at which thread was swinging is 120°

Mgsin = mv²/l

v² = lgsinФ

1/2m . 7gl/2 = 1/2mv² + mg ( l + lsinФ )

SinФ = 1/2, Ф= 30

Therefore,  

Total angle = 90 + 30  

= 120°

Therefore, the angle at which thread was swinging is 120°