Answer: Only Tech B is correct.
Explanation:
First, tech A is wrong.
The circuits that can be compared with links in a chain are the series circuit, and it can be related to the links in a chain because if one of the elements breaks, the current can not flow furthermore (because the elements in the circuit are connected in series) while in a parallel circuit if one of the branches breaks, the current still can flow by other branches.
Also in a parallel circuit, the sum of the currents of each path is equal to the current that comes from the source, so Tech B is correct, the total current is equal to the sum of the currents flowing in each branch of the circuit.
Answer:v=3.28 m/s
Explanation:
Given
mass of rock 
diameter of circle 
radius 
At highest Point

At highest Point N=0 because mass is just balanced by centripetal Force
thus 




The railroad tracks will expand because the heat waves make them bigger
Answer:
Like charges repel
Different charges attract
Explanation:
When particles of similar charges are brought together, they repel each other and increase the distance of separation. Repulsion occurs because both two electrons have negative electrical charge forcing their lines of force to repel. However, when particles of opposite charges are brought nearer to each other, they attract each other and reduce the distance of separation.
This is simple as power in watts is equal to joules per second so we can do 1500 joules divided by 30 seconds which equals 50 watts