Question

an object is dropped from a height [h] with initial velocity zero strikes the ground with a velocity of 30m/s how long does it take to reach the ground also find 'h' [g=10m/s to the power 2]

Answer 1

velocity of a free falling body (starting from rest ) just before hitting ground is given by

sqrt of 2gh
so squaring both sides

v square = 2gh
900 = 20h
h= 45m

now h = ut +1/2at^2
45 = 1/2 × 10 t^2
t = 3sec

Answer 2

Answer:

s = 45m

t = 3 seconds

Explanation:

GIVEN DATA:

u = 0 m/s

v = 30 m/s

a = g = 10m/s

1)

v² - u² = 2as

(30)² - (0)² = 2 x 10 x s

900 / 20 = s

s = 45m

2)

v = u + at

30 = 0 + 10t

30/10 = t

t = 3 seconds

I hope it will help you..