Electric motors require electricity to move the motor parts and do work (like an electric fan).
Elecgric generators actually burn diesel fuel to spin a motor around and around and around to GENERATE, or MAKE, electricity that you can then use to power your fans and lights in your house.
Answer:
44J
Explanation:
Given parameters:
Mass of rock = 0.22kg
Initial velocity = 20m/s
Distance moved = 10m
Unknown:
Initial kinetic energy of the rock = ?
Solution:
To solve this problem, we need to understand that kinetic energy is the energy due to the motion of a body.
It is mathematically expressed as;
Kinetic energy =
m v²
m is the mass
v is the velocity
Kinetic energy =
x 0.22 x 20² = 44J
The concept required to perform this exercise is given by the coulomb law.
The force expressed according to this law is given by

Where,

q = charges of the objects
r= distance/radius
Our values are previously given, so

Replacing,



The force acting on the block are given by,




Therefore the box is accelerated upward.
Answer:
0.22 m
Explanation:
We are told that the driver can survive an acceleration of 50g only if the collision lasts no longer than 30 ms. So,

The acceleration is

where the negative sign is due to the fact that this is a deceleration, since the driver comes to a stop in the collision.
First of all, we can find what the initial velocity of the car should be in this conditions by using the equation:

And since the final velocity is zero, v=0, and solving for u,

And now we can find the corresponding distance travelled using the equation:

Answer:
<em>A) Beam B carries twice as many photons per second as beam A.</em>
Explanation:
If we have two waves with the same wavelength, then their intensity is proportional to their power, or the energy per unit time.
We also know that the amount of photon present in an electromagnetic beam is proportional to the energy of the beam, hence the amount of beam per second is proportional to the power.
With these two facts, we can say that the intensity is a measure of the amount of photon per second in an electromagnetic beam. So we can say that <em>beam B carries twice as more power than beam A, or Beam B carries twice as many photons per second as beam A.</em>