Question

A freely falling body covers half of its journey from
the top of a building in 1 s. What is the height of
the building? (g = 10 m/s)
(1) 20 m
(2) 10m
(3) 5 m
(4) 9m ​

Answer 1

Answer:

20 m. g=10 so the building will be 2×10=20

Answer 2

Given,

Time taken by a free-falling body to cover half of its journey = 1 s

g = 10 m/s

To Find,

The height of the building =?

Solution,

We can solve the question using the following steps:

Let the height of the building be = $h$

In 1 s, the distance covered by the body = $\frac{h}{2}$

We know,

$S = ut + \frac{1}{2} gt^{2}$

Substituting the given values,

$\frac{h}{2} = 0 + \frac{1}{2} *10*1^{2}$.       (SInce the body covers $\frac{h}{2}$ distance in 1 s)

$\frac{h}{2} = 5$

$h = 10m$

Hence, the height of the building is option (2) 10m.