Question

an object is dropped from the top of a building which is 75 meters high. what's it's velocity before it reaches ground

Answer 1

Hi there! :)

$\large\boxed{38.34 m/s}$

Use the following kinematic equation to solve:

$v_{f}^{2} = v_{i}^{2} + 2ad$

Where:

vf = final velocity (?)

vi = initial velocity (0 m/s, object started at rest)

a = acceleration (gravity = 9.8 m/s)

d = distance travelled (75 m)

Plug in the given values into the equation:

$v_{f}^{2} = 0^{2} + 2(9.8)(75)$

Simplify:

$v_{f}^{2} = 2(9.8)(75)\\\\v_{f}^{2} = 1470$

Take the square root of both sides:

$v_{f} = \sqrt{1470} = 38.34 m/s$