Answer:
Average atomic mass = 3.9 amu
Explanation:
Given data:
Percent abundance of He-2 = 0.420%
Percent abundance of He-3 = 2.75%
Percent abundance of He-4 = 96.83%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass) / 100
Average atomic mass = (0.420×2)+(2.75×3) +(96.83×4)/100
Average atomic mass = 0.84 + 8.25 +387.32 / 100
Average atomic mass = 396.41 / 100
Average atomic mass = 3.9 amu.
Work = Fdcos(alpha)
Where F is force, D is distance, and Alpha is the angle to the parallel plane (in this case the ground)
I’ll assume alpha is 0 since it’s not given
100 • 12 • cos(0) = 1200 ft-lbs
