In the first case, the force acting on the spring is the weight of the mass:
This force causes a stretching of
on the spring, so we can use these data to find the spring constant:
In the second case, the first mass is replaced with a second mass, whose weight is
And since we know the spring constant, we can calculate the new elongation of the spring:
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
A big part of the reason that mirrors are seldom if ever used to generate
electricity is the simple fact that there is no way to generate electricity using
mirrors. They are as useless for the purpose as smoke is, although there are
those who have used both items simultaneously to create the impression that
they have succeeded in that attempt.
Answer:
<em>B) 1.0 × 10^5 V</em>
Explanation:
<u>Electric Potential Due To Point Charges
</u>
The electric potential produced from a point charge Q at a distance r from the charge is
The total electric potential for a system of point charges is equal to the sum of their individual potentials. This is a scalar sum, so direction is not relevant.
We must compute the total electric potential in the center of the square. We need to know the distance from all the corners to the center. The diagonal of the square is
where a is the length of the side.
The distance from any corner to the center is half the diagonal, thus
The total potential is
Where V1 and V2 are produced by the +4\mu C charges and V3 and V4 are produced by the two opposite charges of 
. Since all the distances are equal, and the charges producing V3 and V4 are opposite, V3 and V4 cancel each other. We only need to compute V1 or V2, since they are equal, but they won't cancel.
The total potential is
<u>Answer:</u>
The acceleration of the car is 
<u>Explanation:</u>
In the question it is given that car initially heads north with a velocity 
. It then accelerates for 
and in the end its velocity is 
.
initial velocity 
time 
final velocity 
The equation of acceleration is
The value of acceleration is positive, here since the car is speeding up. If it was slowing down the value of acceleration would be negative.
