The magnitude of the force<span> a 1.5 x 10-3 C charge exerts on a 3.2 x 10-4 C charge located 1.5 m away is 1920 Newtons. The formula used to solve this problem is:
F = kq1q2/r^2
where:
F = Electric force, Newtons
k = Coulomb's constant, 9x10^9 Nm^2/C^2
q1 = point charge 1, C
q2 = point charge 2, C
r = distance between charges, meters
Using direct substitution, the force F is determined to be 1920 Newtons.</span>
Answer:
a) r=4.24cm d=1 cm
b) 
Explanation:
The capacitance depends only of the geometry of the capacitor so to design in this case knowing the Voltage and the electric field


The distance must be the separation the r distance can be find also using

But now don't know the charge these plates can hold yet so
a).
d=0.01m



b).


Newton's third law says:
"<span>For every action, there is an equal and opposite reaction. ".
So, the force that Tom does on the sister is equal to force the sister applies on Tom:
</span>

<span>where the label "t" means "on Tom", while the label "s" means "on the sister".
From Newton's second law, we also know
</span>

where m is the mass and a the acceleration. <span>so we can rewrite the first equation as
</span>

<span>And find Tom's acceleration:
</span>

<span>
</span>
A sound wave. Because in a vacuum there is no medium in a vacuum. And the only wave that requires a medium to travel through is a sound wave.