A hiker climbs 500m in elevation gain as he walks a mountain trail. What is the approximate difference in pressure from the start of the elevation gain to after the climb? (Consider air incompressible, acceleration from gravity = 10m/sec2, and density of air = 1.2kg/m3.)

a) 12 Pa

b) 500 Pa

c) 5000 Pa

d) 6000 Pa

**Explanation**

The pressure change for an incompressible column of fluid is given by P=ρgh, where ρ is fluid density, g is acceleration due to gravity, and h is the height of the column of fluid. 1.2kg/m3 x 10m/sec2 x 500m = 6000Pa pressure difference.

a) 12 Pa, incorrect, This answer neglects the height of the column of fluid.

b) 500 Pa, incorrect, This answer neglects gravity and air density.

c) 5000 Pa, incorrect, This answer neglects air density.

d) 6000 Pa, correct.