a man whirls a stone round his head on d end of a string 4m long.

 

 if d stone has a mass of 0.4kg & d string will break if d tension in it exceeds 8N , den d smallest angle d  string can make with d horizantal is [ans 30^0]

 

 

 

i guess,aap ke problem main thodi extra information di gayi hai........

in the sense that for vertical eqbm. we have Tsin@ = mg

by which we get @=30degs.....

but i donno why the velocity is given.....or do we have to calculate the velocity ....in that case we have Tcos@=mv2/R .....

solving for v at T=8N m=0.4Kg, and R=Lcos@

we have v=7.7m/s.........