Question

please solve this 75th problem​

Answer 1

This, question can be divided in 2 parts.

1). Free Fall

2). Retarded Fall.

1). Initial Velocity = u = 0

t = 10 sec.

So, displacement (h1) = (gt^2)/2

h1 = 10×10×10/2

h1 = 500 metres.......●

Now, velocity after 10 second will be the initial velocity for the retarded fall(2nd part).

which is,

v' = gt.....(v = u + gt)

v' = 10×10

v' = 100 m/s

2). Initial Velocity = u = v' = 100m/s

Final Velocity = v = 8m/s

And retardation = a = -2m/s^2

So, displacement (h2) =>

v^2 = u^2 + 2as ....

8^2 = 100^2 - 2×(-2)×h2

h2 = (10000-64)/4

h2 = 9936/4

h2 = 2484 metres......●

So, Total height = h1 + h2

H = 500 + 2484

H = 2984 metres....●●

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Hope it was helpful.