Answer:

Explanation:
Let the charge on the ball bearing is q.
charge on glass bead, Q = 20 nC = 20 x 10^-9 C
Force between them, F = 0.018 N
Distance between them, d = 1 cm = 0.01 m
By use of Coulomb's law in electrostatics

By substituting the values


Thus, the charge on the ball bearing is 
displacement is given by equation

now at t = 5 s the position is

similarly position at t = 9 s

so the displacement of object in given interval of time will be

time interval

now the average velocity will be given as


so its average speed is 252 m/s
Answer:
Explanation:
Let the critical angle be C .
sinC = 1 / μ where μ is index of refraction .
sinC = 1 /1.2
= .833
C = 56°
Then angle of refraction r = 90 - 56 = 34 ( see the image in attached file )
sin i / sinr = 1.2 , i is angle of incidence
sini = 1.2 x sinr = 1.2 x sin 34 = .67
i = 42°.
Answer:They may cause motion to change
Explanation:They may cause motion; they may also slow, stop, or change the direction of motion of an object that is already moving. Since force cause changes in the speed or direction of an object, we can say that forces cause changes in velocity. Remember that acceleration is a change in velocity.
The can be found elsewhere and as follows:
<span>A. of magnetic effects.
B. the ball tries to pull the rod’s electrons over to it.
C. the rod polarizes the metal.
D. the rod and the ball have opposite charges.
</span><span>
I believe the correct answer is option C. If a negatively charged rod is held near a neutral metal ball, the ball is attracted to the rod. this happens because </span>the rod polarizes the metal. Hope this answers the question.