Question

Taking the density of air to be 1.29 kg/m^3, what is the magnitude of the linear momentum of a cubic meter of air moving with the following wind speed of 15 km/h?

Answer 1

Answer:

Momentum p = 5.375 kgm/s

Explanation:

Given

Density $\rho = 1.29 kg/m^3$

Volume $V = 1 m^3$

Velocity $v = 15 km/h$

Solution

Mass  = Density x  volume

$m = \rho \times V\\\\m = 1.29 \times 1\\\\ m = 1.29 kg$

velocity

$v = 15 km/h\\\\v = \frac{15}{3.6} m/s\\\\v = 4.17 m/s$

Momentum = mass x velocity

$p = m \times v\\\\p = 1.29 \times 4.17\\\\p=5.375 kgm/s$

Answer 2

Density = mass divided by volume.So, the mass = density times volume.mass = 1.29 x 1 kglinear momentum is defined as mass times velocityso the linear momentum of a cubic metre at 15,000 m per hour would be 1.29 x 15km/h. The units would be kg km/h, which are not the SI units. These are kg m/s. To get to them the speed has to be converted into metres per second.