A small metal sphere, carrying a net charge of q1 = -2.40?C , is held in a stati

Question

A small metal sphere, carrying a net charge of q1 = -2.40?C , is held in a stationary position by insulating supports. A second small metal sphere, with a net charge of q2 = -8.00?C and mass 1.80g , is projected toward q1. When the two spheres are 0.800 m apart, q2 is moving toward q1 with speed 22.0 m/s (Figure 1) . Assume that the two spheres can be treated as point charges. You can ignore the force of gravity.

A) What is the speed of q2 when the spheres are 0.430m apart?

B) How close does q2 get to q1?

Explanation / Answer

since both are negative charges

so force will be repulsive

as the q2 moves towards q1, its speed will decrease

when they are 0.8 m apart, its speed is 22 m/s

Force at this point

F1=kq1q2/0.82=ma

so a=F1/m

v2-u2=-2as

so u2=v2+2as

in second case

r2=0.43 m

F2=kq1q2/r22=ma=m(v12-u2)/2s

equating

F2(2s)/m+u2=v12

part b)

it will get close to distance r where v=0, that is

kq1q2/r2=m(u2/2s)

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.