Physics Help - Conversion Problems

 Continuing our journey through Physics. Problems solved are from Fundamentals of Physics, Halliday, Resnick, Walker

18. Suppose your hair grows at the rate of 1/32 in. per day. Find the rate at which it grows in nanometers per second. Since the distance between atoms in a molecule is on the order of 0.1nm , your answer suggest how rapidly layer of atoms are assembled in this protein synthesis.

To answer this quesstion we go through the conversion calculations as follows:

(1/32) in/day  x  2.54 cm/in  x 1/100 m/cm  x 10^9/1 nm/m x 1d/24h x 1h/60mins x 1min/60s =

9.19 mm/s

 

Our next problem simply requires us to express the area in the more popular dimensions of square area.  Conversion is as possible

100ft x .305m/ft = 30.5m

150ft x .305m/ft = 45.75m

A = 1395m^2

 

The first task is to express volume in square ft.  By doing conversion calculations we get

131ft x 66ft x 39ft = 337194 ft^3

To get the weight of air we multiply Volume by density to get mass.

337194ft^3 x 0.076lbs/ft^3 =2.5627 lbs