B. Sound, because everything else sits still and sound waves move
Answer:
The visible light frequency is 400 THz to 700 THz, approximately. A THz is a Terahertz, which is a unit of frequency equal to one trillion Hertz.
Answer:
A. If the sum of the external forces on an object is zero, then the object must be in equilibrium
Explanation:
Equilibrium, in physics, the condition of a system when neither its state of motion nor its internal energy state tends to change with time.
For a single particle, equilibrium arises if the vector sum of all forces acting upon the particle is zero.
the object is at equilibrium, then the net force acting upon the object should be 0 Newton. Thus, if all the forces are added together as vectors, then the resultant force (the vector sum) should be 0 Newton.
There are three types of equilibrium: stable, unstable, and neutral
