Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • NCERT
  • Ten small planes are flying at a speed of 150 km/h in total darkness in an air space that is 20 × 20 × 1.5 km3 in volume. You are in one of the planes, flying at random within this space with no way of knowing where the other planes are.

Ten small planes are flying at a speed of 150 km/h in total darkness in an air space that is 20 × 20 × 1.5 km3 in volume. You are in one of the planes, flying at random within this space with no way of knowing where the other planes are. On the average about how long a time will elapse between near collision with your plane. Assume for this rough computation that a safety region around the plane can be approximated by a sphere of radius 10m.

Answers (1)

The motion of molecules in a confined space can be considered a plane. Mean free path λ can be considered as distance travelled by molecules between two planes to avoid any collision, time = distance/speed

 =\frac{\lambda }{v}=\frac{1}{\sqrt{2n}\pi d^{2}.v}

Number of particles per unit volume V = N/volume

N =\frac{10}{20\times 20 \times 1.5} km^{3} = \frac{0.0167}{km^{3}}

d = 2 \times 10 = 20m = 150 km/hr

so, time 

=\frac{1}{\sqrt{2n}\pi d^{2}. V} \\= \frac{1}{1.414 \times 0.0167\times 3.14\times 20 \times 20\times 10^{-6}\times 150 }\\\\= 225 hours.

Posted by

infoexpert24

View full answer

Similar Questions

Latest Question