Here is your answer:
1. A alternating current is a current "is an electric current which periodically reverses direction." A direct current is a "<span>current which flows only in one direction."
2. They are alike because both are "they both are able to travel in different directions." How they are not alike is that a "alternating current travels in a reverse direction but a direct current can only travel in one direction each current."
Hope this helps!</span>
When a liquid is heated, the molecules gain kinetic energy. As the liquid begins to boil they have enough energy to break the intermolecular attractions between their neighbors. This happens first at the surface before the volume below has enough energy to boil. Thus you see high energy water molecules escaping from the surface as mist.
Answer:
The problem occurs with all spherical mirrors.
Spherical mirrors are practical up to about inches in diameter.
Reflecting telescopes use spherical mirrors for apertures up to about 4 ".
Larger aperture telescopes use parabolic mirrors to obtain sharp focus.
Answer:
A) By applying a known force, and measuring it's acceleration.
Explanation:
This is actually something that astronauts do in space as a mathmatical exercise when calculating the mass of an object since F = m × a.
Once the force, and acceleration are applied, the only unknown is the mass which can be solved by dividing force over acceleration. This is because inertial mass is equal to gravitational mass.
