Answer:
<h2>Your skull protects the most important part of all, the brain. You can feel your skull by pushing on your head, especially in the back a few inches above your neck.</h2>
Explanation:
Soil.............................
Answer:

Explanation:
The potential energy of the spring or the work done by the spring is given by :
............(1)
k is the spring constant
d is the compression
When the spring is compressed a distance d' = d/3, let W' is the work is required to load the second dart. Then the work done is given by :

.............(2)
Dividing equation (1) and (2) :



So, the work required to load the second dart compared to that required to load the first is one-Ninth as much. Therefore, the correct option is (E).
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