A pump is used to empty a 5200 L wading pool. The water exits the 3.0-cm-diameter hose at a speed of 2.2 m/s. How long will it take to empty the pool? Express your answer using two significant figures.

55.79 minutes

Explanation:

Volume of water = 5200 L = 5.2 m^3

Diameter = 3 cm

radius, r = 1.5 cm = 0.015 m

v = 2.2 m/s

The volume of water coming out in 1 second = velocity x area

= 2.2 x 3.14 x 0.015 x 0.015

= 1.55 x 10^-3 m^3

1.55 x 10^-3 m^3 water flows = 1 second

5.2 m^3 water flows = 5.2 / (1.55 x 10^-3) = 3345.57 second

= 55.79 minutes