Question

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 above the horizontal
plane will be - (g = 9.8 m/sec? ]​

Answer 1

Time of flight=4+5=9 s

so,

g

2usinθ

=9

or usinθ=

2

9g

if h is the height of P, then

h=(usinθ)4−

2

1

g(4)

2

=

2

9g

×4−

2

1

g×16

=10g=

Answer 2

Yo

total time of flight is =4+5=9 seconds

since the gravity is same we can say half of the journey is covered in 9/2 seconds

by applying the formula

T=2usinx/g

9=2usinx/g

9g/2=usinx

we also know that

s=ut+gt²/2

s=usinx*4-g*16/2

=18g-8g

=10g

=98m

Hope this helps