Question

In the last second of a free fall, a body covered half its total path. From what height and for how many seconds did the body fall? Give two solutions.

Answer 1

Answer: h ≅ 57m; t = 3.4sec.

Explanation:

The equations for the length of paths AC and AB (Fig.) 194 travelled by the body from the beginning of the fall are  

AC = h = 1/2(gt²) and AB = 1/2(h) = 1/2g(t - 1)²,

where t is the time of fall from A to C. The solution of these equations gives the values of t and h.

Alternative solution: We consider the equations for the two paths AB and BC. The equation for AB is