Question

If an object is dropped from the top of buildings and its reaches the grounc at t=4s then the height of building is ( ignoring air resistance) g=9.8ms2

​

Answer 1

Answer:

The height of the building is 78.4 m.

Explanation:

Given that,

Time t = 4 s

When an object is dropped from the top of a building and it reaches the ground.

Then the initial velocity u = 0

Using equation of motion

s=ut+1/2 gt^2...(I)

Where, u = initial velocity

g = acceleration due to gravity

t = 4s

Put the value of t and g in equation (I)

s=0+1/2×9.8×4×4

s=78.4m

Hence, The height of the building is 78.4 m.