Question

Question #35de3

Answer 1

`2.71s`, rounded to two decimal places.

Explanation:

Free fall under gravity is governed by the kinematic equation
`h=ut+1/2g t^2`
Where `h` is height from which body starts falling,
`u` is its initial velocity
`g` is acceleration due to gravity and is `9.81ms^-2`
and `t` is the time taken for the fall to reach ground level.

In this question we take ground level as the sea level. Inserting given quantities we get
`36=0xxt+1/2xx9.81xx t^2`
`=>1/2xx9.81xx t^2=36`
`=> t^2=(36xx2)/9.81`
`=> t=sqrt((36xx2)/9.81)`
`=>t=+-2.71`, rounded to two decimal places.
ignoring the `-ve` root as time can not be negative
`t=2.71s`