Why did Anthony write the hanging bulb?
In a closed room an electric bulb is hanging from the roof and the center of the bulb touches your head and you know your own height Find out what is the height of the room?
How does the force of gravity a light bulb itself that is hanging from a single cord comepare to the force of the cord on the bulb?
The weight of the bulb, acting downward, and the tension in the cord, acting upward, must be equal, so that the net force on the bulb is zero. If not, then the bulb is accelerating in the direction of the net force. If it's just hanging there and not accelerating up or down, then the two forces must be equal, and add up to zero.