31 If 4 seconds be the time in which a projectile reaches a point 'P' of its path and 5 - Physics - Motion In A Plane

Question

31 If 4 seconds be the time in which a projectile reaches a point
'P' of its path and 5 seconds the time from 'P' till it reaches the
horizontal plane through the point of projection The height of P
from the horizontal plane is

Vara · Accepted Answer

Total time of flight:T=4+5   =9 sExpression for time of flight:T=2usinθgusinθ=gT2          =9g2           =4
5gHeight of point P:From the equations of motion of kinematics:s=ut+12at2h=usinθt-12gt2  =4
5g4-12g42  =4 5×9 84-129 842  =98 m

31.If 4 seconds be the time in which a projectile reaches a point 'P' of its path and 5 seconds the time from 'P' till it reaches the horizontal plane through the point of projection.The height of P from the horizontal plane is