Phsx 2220 — Homework #1
22-1. What would be the electrostatic force between two 1.00 C charges
separated by a distance of (a) 1.00 m and (b) 1.00 km if such a
configuration could be set up?
22-2. What must be the distance between point charge q1 = 26.0 µC and
point charge q2 = -47.0 µC for the electrostatic force between them
to have a magnitude of 5.70 N?
22-3. Two equally charged particles, held 3.2 x 10-3 m apart, are released
from rest. The initial acceleration of the first particle is
observed to be 7.0 m/s2 and that of the second to be 9.0 m/s2. If
the mass of the first particle is 6.3 x 10-7 kg, what are (a) the
mass of the second particle and (b) the magnitude of the charge of
each particle?
22-4. The figure at right shows two charges, q1
and q2, held a fixed distance d apart.
(a) What is the magnitude of the
electrostatic force that acts on q1?
Assume that q1 = q2 = 20.0 µC and d =
1.5 m. (b) A third charge q3 = 20.0 µC is
brought in and places as shown at right.
What now is the magnitude of the
electrostatic force on q1?
22-5. In the figure at right, what are the horizontal and
vertical components of the resultant electrostatic
force on the charge in the lower left corner of the
square if q = 1.0 x 10-7 C and a = 5.0 cm?
22-6. Two small, positively charged spheres have a
combined charge of 5.0 x 10-5 C. If each sphere is
repelled from the other by an electrostatic force
of 1.0 N when the spheres are 2.0 m apart, what is
the charge on each sphere?
22-7. Two fixed particles, of charges q1 = +1.0 µC and q2 = -3.0 µC are
10 cm apart. How far from each should a third charge be located so
that no net electrostatic force acts on it?
22-8. (a) What equal positive charges would have to be placed on Earth
and on the Moon to neutralize their gravitational attraction? Do
you need to know the lunar distance to solve this problem? Why or
why not? (b) How many thousand kilograms of hydrogen would be
needed to provide the positive charge calculated in (a)?
