It is a field of study that make direct use of phenomena that is "quantum-mechanincal", such as superposition and entanglement. It's used to perform operations on data
Explanation:
For equilibrium,
.
So,
= 0

= 
= 705.6 N
Also, for equilibrium
= 0
= 0
or, 
= 
= 176.4 N
Thus, we can conclude that the tension in the first rope is 176.4 N.
Answer:
Yes
Explanation:
If lamp A burnt out there would still be a wire above it that connects lamp B and C to the power source
Answer : The static friction depends on two factors
1. Roughness of the surface
2. Force
Explanation : Friction occur when surface is not smooth.
The formula of friction is

Static friction depends on the roughness of the surface and force which is trying to push to object along the surface.
Static friction is caused by the attraction between two surfaces that are in contact. when the surface will rough and the object will heavier then the force will be larger.
All it does is lets him pull in a more convenient direction to raise the load. It has no effect on the required force.