let the length of the beam be "L"
from the diagram
AD = length of beam = L
AC = CD = AD/2 = L/2
BC = AC - AB = (L/2) - 1.10
BD = AD - AB = L - 1.10
m = mass of beam = 20 kg
m₁ = mass of child on left end = 30 kg
m₂ = mass of child on right end = 40 kg
using equilibrium of torque about B
(m₁ g) (AB) = (mg) (BC) + (m₂ g) (BD)
30 (1.10) = (20) ((L/2) - 1.10) + (40) (L - 1.10) 
L = 1.98 m 
 
        
             
        
        
        
Answer:
9266 feet
Explanation:
with Earth's gravity and long it fell that's as good as it gets if there was no other factors like wind mass weight but your welcome
 
        
             
        
        
        
Answer:

Explanation:
a) Fundamental frequency
A harmonic is an integral multiple of the fundamental frequency.


b) Wave speed
(i) Calculate the wavelength
In a  fundamental vibration, the length of the string is half the wavelength.

(b) Calculate the speed
s



 
        
             
        
        
        
Well, first of all, I don't think "After the collapse of a nebular cloud ..." 
is the first time that "atoms begin gravitating together".  Seems to me like 
that's what was going on all the time, and it's what caused the nebular cloud 
to collapse in the first place.
In any case, once the pressure and temperature at the center get high enough, 
you get "ignition" of nuclear fusion, and that's when you first have a "star".