Molecule Kinetics: Calculating Temperature from Speed Upon Moon Re-Entry

[bpw91284]

Homework Statement

A space vehicle returning from the Moon enters Earth’s atmosphere at a speed of about 4.9E4 km/h. Molecules (assum nitrogen) striking the nose of the vehicle with this speed correspond to what temperature?

Homework Equations

KE=0.5mv^2=kT
k: constant

The Attempt at a Solution

I'm lost.

 

[Dick]

Look up the mass of an N2 molecule and Boltzmann's constant, k, put them into your first equation and solve for T. ?

 

[bpw91284]

Look up the mass of an N2 molecule and Boltzmann's constant, k, put them into your first equation and solve for T. ?

Can't look up mass, only molecular weight. Where mass=#mols*molecular weight.

 

[Dick]

Can't look up mass, only molecular weight. Where mass=#mols*molecular weight.

You can so look up the mass of a single nitrogen atom. It's in the periodic table in atomic mass units. What's an atomic mass unit in kilograms? Can also be looked up.

 

[bpw91284]

You can so look up the mass of a single nitrogen atom. It's in the periodic table in atomic mass units. What's an atomic mass unit in kilograms? Can also be looked up.

N=14.00674u
1 u ≈ 1.66053886 × 10−27 kg

Then just solve for T with 0.5mv^2=kT?

Thanks,
Brandon

 

[Dick]

Except remember the question says 'molecules' and nitrogen is N2 (two nitrogen atoms).