Answer:
Theory
Explanation:
Conservation of energy is explained as a scientific law and not a theory because it does not explain why energy is conserved.
A law is a the statement of a scientific fact. It is a product of repeated experiment and observation through time. Most laws do not explain the reason for the logic behind their premise.
A theory on the other hand provides an explanation for an observed phenomenon. Most theories are no immutable. They are often changed when new finds are reported or made.
Laws are immutable and they stand still.
Answer:
B. They each contain the same amount of matter.
Explanation:
Scientifically, mass is the amount of matter in an object.
A. Whether an object is big or small does not mean that it will be a certain mass. If you have two objects that are the same size, the denser object will have more mass, and the less dense object will have less mass.
C. The amount of space an object takes up is called the volume.
D. Different combinations and amounts of elements can give you the same mass. Rocks, books and cans of soda are made of different things.
Answer:
Commutator is a ring which reverse the direction of current in AC circuit so that the coil connected to it will continuous to move in the same direction.
Explanation:
In motors there exist a coil which is rotated due to torque of magnetic field when current flow through it. Since AC current is used to run the motor so we know that AC current changes its direction after half cycle.
So here commutator plays an important role to reverse the direction of current after every half cycle so that the current goes in same direction always into the coil.
This will produce a constant direction torque on the coil so that it will rotate in same sense always.
So commutator role is to provide same direction current to the coil by reversing its direction after every half cycle
The current will increase at the same rate the voltage does.
