Answer:
a
The magnetic field strength is 
Explanation:
From the question we are told that
The length line above the ground is 
The current of the line is 
The voltage of the line is 
Generally magnetic field strength is mathematically represented as

Where
is the permeability of free space 

![= (2.0*10^{-7})[\frac{200}{20} ]](https://tex.z-dn.net/?f=%3D%20%282.0%2A10%5E%7B-7%7D%29%5B%5Cfrac%7B200%7D%7B20%7D%20%5D)


Earths magnetic field is approximately given as 
So the percentage would be


%
Answer: It would increase.
Explanation:
The equation for determining the force of the gravitational pull between any two objects is:

Where G is the universal gravitational constant, m1 is the mass of one body, m2 is the mass of the other body, and r^2 is the distance between the two objects' centers squared.
Assuming the Earth's mass but not its diameter increased, in the equation above m1 (the term usually indicative of the object of larger mass) would increase, while the r^2 would not.
Thus, it goes without saying that, with some simple reasoning about fractions, an increasing numerator over a constant denominator would result in a larger number to multiply by G, thus also meaning a larger gravitational strength between Earth and whatever other object is of interest.
Work occurs when an applied force results in movement of an object in the same direction as the applied force.
Answer:
those who are attracted to magnets. ex: iron, cobalt and nickel
Answer:
c)
Explanation:
A collision is said to be elastic when the total kinetic energy is the same after the collision. The speed of objects that are stuck together will always be less than the initial speed of the object that was in motion given that the other particle was at rest. It is because the kinetic energy of the system was due to the moving object. The objects have a greater overall mass when they are stuck. If the kinetic energy is the same and the mass increases, the velocity must decrease.