Question

1. Fluid flows at a rate of 2.0 L/s through a pipe with a diameter of 10 cm. The pipe then goes up a height of 5m while narrowing to a diameter of 5 cm. What is the pressure gradient (the change in pressure) from the top to the bottom of the pipe? [hint: draw this and label with P1, v1, P2, v2 etc.)

2. A hurricane wind blows across the top of a flat roof measuring 12 m by 5m at a speed of 120 km/h.

a) Is the air pressure above the roof higher or lower than the pressure inside the house? Explain.

b) Find the pressure difference.

c) How much force is exerted on the roof? If the roof's structure fails, will in

Answer 1

using bernauli's equation is pipe

since speed is same at every point in pipe

pressure difference arises due to height diffeerence

pressure gradient

2(a) pressure on roof is more in lower part than higher part because speed of air on higher part is more than speed in lower part

(b)assuming speed of air is nearly zero in lower part

pressure difference comes from

(c)force exerted on roof =708.55*area

=708.55*12*5

=42513.3 N

roof will blow out because pressur is highr in lower part