Answer:
Two positively charged particles
Explanation:
I said two positively charged particles because if I say c or d what ever it is for you guy it can be wrong so just pick the one that says Two positively charged particles
Answer:
a
The height is 
b
The horizontal distance is 
Explanation:
From the question we are told that
The speed is 
The angle is 
The height of the cannon from the ground is h = 2 m
The distance of the net from the ground is k = 1 m
Generally the maximum height she reaches is mathematically represented as

=> ![H = \frac{(15)^2 [sin (40)]^2 }{2 * 9.8} + 2](https://tex.z-dn.net/?f=H%20%20%3D%20%20%5Cfrac%7B%2815%29%5E2%20%5Bsin%20%2840%29%5D%5E2%20%7D%7B2%20%2A%209.8%7D%20%20%2B%20%202)
=> 
Generally from kinematic equation

Here s is the displacement which is mathematically represented as
s = [-(h-k)]
=> s = -(2-1)
=> s = -1 m
There reason why s = -1 m is because upward motion canceled the downward motion remaining only the distance of the net from the ground which was covered during the first half but not covered during the second half
a = -g = -9.8

So

=> 
using quadratic formula to solve the equation we have

Generally distance covered along the horizontal is

=> 
=> 
One-dimensional motion can be plotted through the Cartesian plane which has a coordinates of (x,y). These coordinates are the abscissa and ordinates. Since, there are two coordinates, the answer to the second item is two.
The symbol that can be used to identify systems position is (x,y). Since this is one dimensional motion, it is possible that one of the two coordinates becomes zero.