Water? The sun. I DUNNO I FEEL BAD :(
Answer: C) The two particles will move away from each other
Explanation:
When two electrically charged bodies come closer, appears a force that attracts or repels them, depending on the sign of the charges of this two bodies.
This is stated by Coulomb's Law:
"The electrostatic force 
between two point charges 
and 
is proportional to the product of the charges and inversely proportional to the square of the distance 
that separates them, and has the direction of the line that joins them"
Mathematically this law is written as:
Where 
is a proportionality constant.
Now, if and have the same sign charge (both positive or both negative), a repulsive force will act on these charges.
There's so much going on here, in a short period of time.
<u>Before the kick</u>, as the foot swings toward the ball . . .
-- The net force on the ball is zero. That's why it just lays there and
does not accelerate in any direction.
-- The net force on the foot is 500N, originating in the leg, causing it to
accelerate toward the ball.
<u>During the kick</u> ... the 0.1 second or so that the foot is in contact with the ball ...
-- The net force on the ball is 500N. That's what makes it accelerate from
just laying there to taking off on a high arc.
-- The net force on the foot is zero ... 500N from the leg, pointing forward,
and 500N as the reaction force from the ball, pointing backward.
That's how the leg's speed remains constant ... creating a dent in the ball
until the ball accelerates to match the speed of the foot, and then drawing
out of the dent, as the ball accelerates to exceed the speed of the foot and
draw away from it.
Answer:
Part A: What is the duck's speed? v=0.2m/s
Part B: How far apart are the crests behind the duck = 1m
Explanation:
The concept applied here is the DOPPLER EFFECT, for example, if one is driving towards a station at 120km/hr, a higher frequency will be heard. and if you are driving away from the station at the same speed, one will hear a much more lower frequency. Tthese effect was proposed by the Austrian physicist by name Johann Christian doppler.
The detailed steps and appropriate formula is as shown in the attached file.
