The ball rolled a distance of
d = 12m + 20m.
But the change of position is
x = + 12m - 20m
The Greek philosopher Aristotle and the Roman Catholic Church also believed the sun revolved around the earth. In 1543, Nicolaus Copernicus<span> published a new theory stating the earth revolves around the sun. This is known as the Copernican theory.</span>
Answer:
the field at the center of solenoid 2 is 12 times the field at the center of solenoid 1.
Explanation:
Recall that the field inside a solenoid of length L, N turns, and a circulating current I, is given by the formula:
Then, if we assign the subindex "1" to the quantities that define the magnetic field (
) inside solenoid 1, we have:

notice that there is no dependence on the diameter of the solenoid for this formula.
Now, if we write a similar formula for solenoid 2, given that it has :
1) half the length of solenoid 1 . Then 
2) twice as many turns as solenoid 1. Then 
3) three times the current of solenoid 1. Then 
we obtain:

This is a "trick" question.
If the elevator is traveling at constant speed, it means it is at rest. This means anything inside the elevator traveling at constant speed, weights the same as in an elevator not moving -also at rest-.
So the 100N weight's weight doesn't change in an elevator traveling at constant speed.
Answer:
The door will move when the forces exerted by each individual becomes unbalanced.
Explanation:
The Door will only move when the forces exerted by each of the individual is unbalanced i.e. when the Torque is unbalanced
This is because there will only be a reaction or movement of an object when the applied force > resistant force acting on the object.
example : An object at rest will only move when the applied force is greater than the frictional forces acting on the object at rest.