The shoreline would be your
reference point.
A reference point, in physics, is some point in space used to illustrate the location or position of other things, relative to this reference point. So in this case, the shoreline is considered as the reference point to locate the position of the surfers.
Answer:
E = 0.437 N/C
Explanation:
Given that,
Charge, 
Electric force, 
Let the strength of the electric field is E. We know that, the electric force is given by :
F = qE
Where
E is the electric field strength

So, the strength of the electric field is equal to 0.437 N/C.
Answer:
1 joule = 0.737 foot-pound
Joule is the unit of work.
1 J = 1 N·m
In SI units
1 J = 1 kg· m/s²
0.737 foot-pound is the amount of work to raise 0.737 pounds one foot or raising one pound to 0.737 ft.
The answer is 0
potential energy= mass• gravity (9.8m/s)• height.
Your mass 3kg. I believe your need to convert this to grams (3000g) and then multiply by 9.8. Since your height is 0 because the ball is on the ground then your potential energy is 0
This is a ball and socket joint.