Question

Scientists have investigated how quickly hoverflies start beating their wings when dropped both in complete darkness and in a lighted environment. Starting from rest, the insects were dropped from the top of a 50 - cm tall box. In the light, those flies that began flying 200 m s after being dropped avoided hitting the bottom of the box 87 % of the time, while those in the dark avoided hitting only 25 % of the time.

Required:
a. How far would a fly have fallen in the 200 ms before it began to beat its wings?
b. How long would it take for a fly to hit the bottom if it never began to fly? In seconds.

Answer 1

Step-by-step explanation:

a )

Hoverfly will fall with acceleration equal to g .

Initial velocity of fall of hoverflies u = 0

displacement ( vertical ) h = ?

time t = 0.2 s

acceleration due to gravity g = 9.8 m / s²

h = ut + 1/2 g t²

= 0 + .5 x 9.8 x .2²

= .196 m

= 19.6 cm

b )

Time taken to fall by 50 cm or 0.5 m under free fall from initial position .

.5 = 0 + .5 x 9.8 t²

t² = .1020

t = .319 s = 319 ms .