I attached a Diagram for this problem.
We star considering the system is in equlibrium, so
Fm makes 
with vertical
Fm makes 70 with vertical
Applying summatory in X we have,
We know that W is equal to
Substituting,
<em>For the second part we know that the reaction force Fj on deltoid Muscle is equal to Fm, We can assume also that</em> 
The strength of the electric and magnetic fields there is no physical "distance" of oscillation here. nothing is actually moving up and down if you draw light as a sinusoidal wave, the up and down motion is the strength of the EM fields cheers
Force = mass * acceleration
F = ma
8 N = 2 kg * a
8 = 2a
2a = 8
a = 8/2 = 4
acceleration = 4 m/s²
Because metric units use the deca system, 1km = 1000m = 100 000cm etc...
