Question

a stone is dropped from the height of height of 90 m with what velocity does it reach to the ground?

Answer 1

Let the velocity by which the object will fall be ''v''.

Initial Velocity(u) = 0

Height = 10 m.Acceleration due to gravity = 9.8 m/s².

Using the Third' Galileo's equation of motion,

v² - u² = 2gS

⇒ v² - 0² = 2 × 9.8 × 10

⇒ v² = 196

∴ v = 14 m/s.

Hence, the velocity by which the Object will fall is 14 m/s.

Hope it helps. :-)

Answer 2

Since the stone needs no velocity to fall,

its initial velocity u= 0

s is the height from which the stone dropped.

v is the velocity with which the stone reach the ground.

By equations of motion

v^2 = u^2 + 2gs

v^2
= 0 + 2 × 9.8 × 90

= 196 × 9

v = 14 × 3 = 42 m / s

I hope this answer helps you