Answer:
0.702 m
Explanation:
The magnitude of the electrostatic force between two charged objects is given by Coulomb's Law:

where
k is the Coulomb's constant
q1, q2 are the two charges
r is the separation between the objects
And the force is:
- Attractive if the two charges have opposite signs (+-)
- Repulsive if the two charges have same sign (++ or --)
In this problem we have:
is the force between the two balls
is the charge on each ball
Solving for r, we find the separation between the balls:

Answer:
Regular reflection occurs when a beam of light falls on a smooth and polished surface and irregular reflection occurs when a beam of light falls on a rough surface. Since the surface is uneven, from different points light rays get reflected in different directions and give rise to irregular reflection.
I would say B. hope it helps
Answer:
Speed of motorcycle is 40 mph and speed of car is 50 mph
Explanation:
Let the peed f the motorcycle is v m /sec
According to question speed of motorcycle = 2v-30 mph
Now it is given that in two hours car is 20 miles ahead from motorcycle
Distance traveled by motorcycle in 2 hour = 2v
And distance traveled by car in two hour = 2×(2v-30)
Now according to question

4v-60 = 2v+20
2v = 80
v = 40 mph
So speed of motorcycle is 40 mph
And speed of car = 2v-30 = 2×40-30 = 50 mph