الفيزياء العامة الجزء الثاني#موقع الفيزياء.كوم

Multiple choice question for part 1
[1] Two small beads having positive charges 3 and 1 are fixed on the
opposite ends of a horizontal insulating rod, extending from the origin to the
point x=d. As in Figure 1, a third small, charged bead is free to slide on the
rod. At what position is the third bead in equilibrium?
+3q +q
d
a. x = 0.366d
b. x = 0.634d
c. x = 0.900d
d. x = 2.37d
Figure 1
[2] Two identical conducting small spheres are placed with their centers
0.300m apart. One is given a charge of 12.0nC and the other one a charge of
18.0nC. (a) Find the electrostatic force exerted on one sphere by the other.
(b) The spheres are connected by a conducting wire. After equilibrium has
occurred, find the electrostatic force between the two.
a. (a) 2.16 10 -5 N attraction; (b) 0 N repulsion
b. (a) 6.47 10 -6 N repulsion; (b) 2.70 10 -7 N attraction
c. (a) 2.16 10 -5 N attraction; (b) 8.99 10 -7 N repulsion
d. (a) 6.47 10 -6 N attraction; (b) 2.25 10 -5 N repulsion
[3] An electron is projected at an angle of 40.0 o above the horizontal at a
speed of 5.20 10 5 m/s in a region where the electric field is E = 3 50 j N/C.
Neglect gravity and find (a) the time it takes the electron to return to its
maximum height, (h) the maximum height it reaches and (c) its horizontal
displacement when it reaches its maximum height.
a. (a) 1.09 10 -8 s; (b) 0.909 mm; (c) 2.17 m
b. (a) 1.69 10 -8 s; (b) 2.20 mm; (c) 4.40 m
c. (a) 1.09 10 -8 s; (b) 4.34 mm; (c) 0.909 m
d. (a) 1.30 10 -8 s; (b) 1.29 mm; (c) 2.17 m
[4] Two identical metal blocks resting on a frictionless horizontal surface are
connected by a light metal spring for which the spring constant is k 175 N/m
and the unscratched length is 0.350 m as in Figure 2a.
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