The correct answer is matter. Matter is a physical substance, so it is that only option provided that can be broken down to the subatomic particle level.
In some unusual applications of unusual components, I can think of unusual electric circuits where a switch may be connected in parallel with a device in order to control it.
But I'm sure this is not what's intended in a question on the high-school level.
Until you get in a situation with tricky applications in a tricky circuit, your switches will always be connect <em>in series</em> with the devices they control.
Answer:
F = 0 [N]
Explanation:
To solve this problem we must perform a summation of forces in the direction of the vertical axis. Where the positive force is that of the tension of the upward force, while the force exerted by the weight is directed downward with a negative sign.
ΣF = 0
15 - 15 + F = 0
F = 0 [N]
