Question

Please help I got the 4th one I’m not sure if it’s correct

Answer 1

Given data:

* The time taken by the box to hit the ground is 6.45 s.

* The initial velocity of the box is 15 m/s.

Solution:

By the kinematics equation, the height of the cliff is,

`H=u_yt+(1)/(2)gt^2`

where u_y is the vertical initial velocity of the box,

The vertical initial velocity of the box is zero,

Substituting the known values,

`\begin{gathered} H=0+(1)/(2)*9.8*6.45*6.45 \\ H=203.9\text{ m} \\ H\approx204\text{ m} \end{gathered}`

Thus, the magnitude of the height of cliff is 204 meter.

Hence, the cliff was - 204 meter tall (measured in upward direction), and 1st option is the correct answer.