Answer:
a) a = 5.03x10¹³ m/s²
b) 
Explanation:
a) The acceleration of the positron can be found as follows:
(1)
Also,
(2)
By entering equation (1) into (2), we have:

<u>Where:</u>
F: is the electric force
m: is the particle's mass = 9.1x10⁻³¹ kg
q: is the charge of the positron = 1.6x10⁻¹⁹ C
E: is the electric field = 286 N/C
b) The positron's speed can be calculated using the following equation:

<u>Where</u>:
: is the final speed =?
: is the initial speed =0
t: is the time = 8.70x10⁻⁹ s

I hope it helps you!
Answer:
The near point of an eye with power of +2 dopters, u' = - 50 cm
Given:
Power of a contact lens, P = +2.0 diopters
Solution:
To calculate the near point, we need to find the focal length of the lens which is given by:
Power, P = 
where
f = focal length
Thus
f = 
f =
= + 0.5 m
The near point of the eye is the point distant such that the image formed at this point can be seen clearly by the eye.
Now, by using lens maker formula:

where
u = object distance = 25 cm = 0.25 m = near point of a normal eye
u' = image distance
Now,



Solving the above eqn, we get:
u' = - 0.5 m = - 50 cm
I believe the answer is C
Answer:
A . Are the masses repelling or attracting
answer:
<em><u>So, positive energy densities ("masses") attract each other by gravitational interaction. This is the general idea.</u></em>
<em><u>B</u></em>. What is the magnitude of the electrical force between the objects<em><u>?</u></em>
<em><u>answer</u></em><em><u>:</u></em>
<em><u> </u></em><em><u>The magnitude of the electrostatic force F between two point charges q1 and q2 is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.</u></em>
C. What would the magnitude of the force be if one of the charges was 1/3 the amount?
answer:
<em><u>0.45</u></em>
D. ) What would the force be if the distance between the charges was only 1 meter (with the original charges)?
answer;
<em><u>Fmin=2.3×10^−28</u></em><em><u>N</u></em>
<em><u>E</u></em><em><u>:</u></em><em><u> </u></em>What would the force be if one of the charges was 1/3 the amount AND the distance was 1 meter?
answer;
<em><u>Electrostatic force is directly related to the charge of each object. So if the charge of one object is doubled, then the force will become two times greater.</u></em>
<em><u>#</u></em><em><u>CARRYONLEARNING</u></em><em><u>:</u></em><em><u>)</u></em>
<em><u>LOVEUALL</u></em>