Answer:
Displacement of object before hitting water surface after 8 seconds = 320 meter
Explanation:
We have equation of motion , [tex]s= ut+\frac{1}{2} at^2[/tex], s is the displacement, u is the initial velocity, a is the acceleration and t is the time.
In this case initial velocity = 0 m/s, acceleration = 10 [tex]m/s^2[/tex], we need to calculate displacement when time = 8 seconds.
[tex]s= 0*8+\frac{1}{2} *10*8^2\\ \\ s=320m[/tex]
So displacement of object = 320 meter
