Question

A meat baster consists of a squeeze bulb attached to a plastic tube. When the bulb is squeezed and released, with the open end of the tube under the surface of the basting sauce, the sauce rises in the tube to a distance h, as the drawing shows. Using 1.013 105 Pa for the atmospheric pressure and 1188 kg/m3 for the density of the sauce, find the absolute pressure PB in the bulb when the distance h is (a) 0.24 m and (b) 0.15 m.

Answer 1

Answer:

a)P(abs)=104.15 KPa

b)P(abs)=103.082 KPa

Explanation:

Given that

P(atm) = 1.013 x 10⁵ Pa

P(atm) = 101.3  KPa

Density ρ = 1188 kg/m³

We know that

Absolute pressure = Gauge pressure + Atmospheric pressure

P(abs)=P(gauge)+P(atm)

When h= 0.24 m

Gauge pressure

P(gauge) =  ρ g h

P(gauge) = 1188 x 10 x 0.24 = 2851.2 Pa

P(gauge) = 2.851 KPa

P(abs)=P(gauge)+P(atm)

P(abs)=101.3 + 2.851 KPa

P(abs)=104.15 KPa

When h= 0.15 m

Gauge pressure

P(gauge) =  ρ g h

P(gauge) = 1188 x 10 x 0.15 = 1782 Pa

P(gauge) = 1.782 KPa

P(abs)=P(gauge)+P(atm)

P(abs)=101.3 + 1.782 KPa

P(abs)=103.082 KPa