Question

How high should a helicopter pilot rise at point A just to see the horizon at point B, if the distance AB is 40 km?

1. 101.75 m
2. 110.50 m
3. 107.68 m
4. 105.50 m

Answer 1

Correct Answer - Option 3 : 107.68 m

Concept:

Maximum distance visible to earth surface from any height is called visible horizon, and it is given by,

d = 3.855 √h

Where, d is in kilometer and h is in meter.

Calculation:

Given:

d = 40 km

40 = 3.855 × √h

h = 107.68 m