Two particles each have a mass of 7.2 x 10-3 kg. One has a charge of +5.3 x 10-6
ID: 2276520 • Letter: T
Question
Two particles each have a mass of 7.2 x 10-3 kg. One has a charge of +5.3 x 10-6 C, and the other has a charge of -5.3 x 10-6 C. They are initially held at rest at a distance of 0.76 m apart. Both are then released and accelerate toward each other. How fast is each particle moving when the separation between them is one-third its initial value?
Two particles each have a mass of 7.2 times 10-3 kg. One has a charge of +5.3 times 10-6 C, and the other has a charge of -5.3 times 10-6 C. They are initially held at rest at a distance of 0.76 m apart. Both are then released and accelerate toward each other. How fast is each particle moving when the separation between them is one-third its initial value?Explanation / Answer
use the conservation of energy
when the two particles are held at a distance r apart, they have only potential energy, and the potential energy between two charges is:
PE=kq1 q1/r
when they are a distance r/3 apart, they have both PE and KE; the conservation of momentum tells us:
total energy before=total energy after
kq1 q1/r = kq1q2/(r/3) + 2(1/2 mv^2)
and we have 2(1/2mv^2) since there are two particles of mass m moving with speed v
the equation above gives us
-2k q1q2/r = mv^2
for k=9x10^9
q1 x q2=-28.09x10^(-12)
m=0.0072
r=0.76m
we have
2*(9x10^9)(28.09x10^(-12)/0.76=0.0072v^2
v=9.71m/s
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.