Problema Solution

1.How many pipes 2 inches in diameter have the same total across sectional area a a pipe 6 inch in diameter

2. If the surface speed of an 8 inch diameter pulley is 4500 ft. per minute, how many RPM is it turning.

Answer provided by our tutors

The cross sectional area of a pipe with 2 inches in diameter is:

(2/2)^2 pi = pi

The cross sectional area of a pipe with 6 inches in diameter is:

(6/2)^2 pi = 9 pi

Since 9pi/pi = 9 follows that 9 pipes with 2 inches in diameter have the same total across sectional area as a pipe with 6 inches in diameter.