Question

Components of ( x ) is ( 4 cos 60^{circ} ) and ( y ) is ( 4 sin 60^{circ} )
At h height distance,
( tan 30^{circ}=mathrm{V} mathrm{y} / mathrm{ucos} 60^{circ} )
( mathrm{Vy}=mathrm{u} / 2 sqrt{3} )
Distance in ( mathrm{y} ) - direction :
( V y^{2}-(u sin 60)^{2}=2 a s )
( (mathrm{u} / 2 sqrt{3})^{2}-(mathrm{u} sqrt{3} / 2)^{2}=-2 mathrm{g} mathrm{s} )
By this ,we get
( u=sqrt{3} g h )

# A stone projected at an angle of 609 from the ground level strikes at an angle of 30° on the roof of a building of height 'h'. Then the speed of projection of the stone is : (A) 2gh (B) V6gh (D) Jgh 60° TI 3gh

Solution