Answer:
A
B

C

D

Explanation:
Considering the first question
From the question we are told that
The spring constant is 
The potential energy is 
Generally the potential energy stored in spring is mathematically represented as 
=>
=>
=>
Considering the second question
From the question we are told that
The mass of the dart is m = 0.050 kg
Generally from the law of energy conservation

=> 
=> 
Considering the third question
The height at which the dart was fired horizontally is 
Generally from the law of energy conservation

Here KE is kinetic energy of the dart which is mathematical represented as

=> 
=> 
=> 
Considering the fourth question
Generally the total time of flight of the dart is mathematically represented as

=> 
=> 
Generally the horizontal distance from the equilibrium position to the ground is mathematically represented as

=> 
=> 
Answer:

Explanation:
The original equation is:

We notice that:
- we have 1 atom of Fe on the left, and 2 atoms of Fe on the right
- we have 2 atoms of O on the left, and 3 atoms of O on the right
Therefore, the equation is not balanced.
In order to balance it, we can add:
- a coefficient 3 in front of 
- a coefficient 2 in front of 
So we have:

Now the oxygen is balanced, but the iron it not balanced yet, since we have 1 Fe on the left and 4 on the right. Therefore, we should add a coefficient 4 on the Fe on the left:

Well, the baselines are 65 feet, and the distance from home plate to pitcher's mound is 50 feet. So I believe your answer would be 50 feet.
Answer:
3.528×10² V.
Explanation:
potential difference: This is the work done when one coulomb of charge moves from one point to another in an electric field. The S.I unit of potential difference is volt. The formula of potential difference is given as,
V = kq/r..................... Equation 1
And
E = kq/r² .................. Equation 2
Comparing equation 1 and equation 2,
V = E×r............................. Equation 3
Where V = potential difference, E = Electric field between the plate of the capacitor, r = distance between the plate.
Given: E = 6.3×10⁵ V/m, r = 0.56 mm = 0.00056 m.
Substitute into equation 3,
V = 6.3×10⁵×0.00056
V = 3.528×10² V.
Hence the potential difference of the plate = 3.528×10² V.