1. Three charges are placed at the corners of an isosceles triangle with base angles of 50°. The base
of the triangle is 2 m long. A + 3 mC charge is placed at the top of the triangle, a – 5 mC charge is
placed at one of the base angles (make it the right corner), and a + 2 mC charge is placed at the
other corner. Calculate the net force acting on the + 2 mC charge.
2. Two identical small charged spheres, each having a mass of 4.0 x 10-2 kg, hang in equilibrium as
shown in figure. The length L of each string is 0.350m and the angle thetha is 5.00. Find the
magnitude of the charge on each sphere.
3. A voltage of 2  107 V is applied across two horizontal metal plates 4 cm apart. A charged
particle of mass m enters the field horizontally and keeps on moving along a straight line in the
field. The width of the plates is 10 cm
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(a)
When the particle enters the electric field, what is the electrostatic force acting on it?
Express the answer in terms of m.
(b)
Suppose m = 8  1026 kg. Find the charge of the particle. Take g = 9.81 m s2.
(c)
The voltage across the plates is increased slightly.
(i)
Sketch a possible path of the particle.
(ii)
In the same figure, sketch the path of the particle if it enters the field from a
slightly higher position. Explain your answer.