Answer:
44 m
Step-by-step explanation:
I'll assume the 5 seconds is from the time he jumped off the board.
This means we are to calculate his height 3 seconds after dropping from the height of 9 m, since he spent 2 seconds springing up off the board from a height of 7 m to the 9 m height.
we use Newton's equation of motion.
We are given
initial velocity U at the height of 9 m = 0 m/s
acceleration due to gravity downwards g = 9.81 [tex]m/s^{2}[/tex]
distance covered S = ?
time of fall t = 3 seconds
we use S = Ut + [tex]\frac{1}{2}[/tex]g[tex]t^{2}[/tex]
S = (0 x 3) + [tex]\frac{1}{2}[/tex](9.81 x [tex]3^{2}[/tex])
S = 0 + 44.145
S = 44 m