Question

An object is dropped from rest from the top of a 400m cliff on earth. if air resistance is negligible, what is the distance that the object travels during the first 6s of its fall?

Answer 1

answer will be 180m as it's free fall apply s = ut + 1/2at^2

Answer 2

During the first 6 seconds of the object’s fall, it travelled 176.4 metre.  

Given:

Initial Velocity of a object (u) = 0 -----------(1)

Acceleration due to gravity (a) = 9.8 m/s2 ---------(2)

Time (t) = 6 seconds -----------(3)

Solution:

Let distance travelled by object = S  

According to kinematic equation,

$\mathrm{S}=\mathrm{ut}+1 / 2 \mathrm{at}^{2}$ ----------------(4)

By substituting values in equation (4) from equation (1), (2) and (3)  

$S=0+\frac{1}{2}(9.8) \times(6)^{2}$

$=\frac{1}{2} \times 352.8$

= 176.4 m.

Hence, distance travelled by object = 176.4 m .