College Physics Problem 1.35


(a) Calculate the number of cells in a hummingbird assuming the mass of an average cell is ten times the mass of a bacterium.

(b) Making the same assumption, how many cells are there in a human?


Solution:

Part a

The mass of a hummingbird is 10-2 kg, while the mass of a cell is 10-15 kg. The number of cells in the hummingbird is

\displaystyle \frac{10^{-2}}{10\left(10^{-15}\right)}=10^{12}\:\text{cells}

Part b

The mass of a person is 102 kg.

\displaystyle \frac{10^2}{10\left(10^{-15}\right)}=10^{16}\:\text{cells}