A lantern hangs from one vertical rope on a porch. It hangs still.
What does a hanging object's free-body diagram look like?
No surface touches the lantern, so there is no normal force on it.
The rope is stretched, and a stretched rope pulls what it holds. That force is a tension.
The diagram carries two arrows: the lantern's weight, straight down, and one tension, straight up, in the line of the rope.
The lantern hangs at rest, so the two arrows are drawn equal.
A birdhouse hangs at rest from one vertical rope. Which forces are on its free-body diagram?
Now consider a framed picture hanging level from two vertical cords.
Each cord is its own stretched rope, and each one pulls the picture: one tension arrow per cord.
So the picture's diagram carries three arrows: the weight down, and two tensions up, one in the line of each cord.
The picture hangs at rest, so together the two tensions balance the weight.
A banner hangs level from two vertical cables. How many tension arrows does its free-body diagram carry?
Each cable runs straight up from the banner. In which direction does each tension on the banner act?
A heavy flower basket hangs at rest from one vertical chain. Build its free-body diagram.
The basket becomes a box.
Its weight: one arrow, straight down.
The stretched chain pulls it: one tension, straight up.
The basket is at rest, so the two arrows are drawn equal.
Two arrows: weight down, one tension up, equal in length.
A porch swing seat hangs level, at rest, from two vertical chains. Build its free-body diagram.
The seat becomes a box.
Its weight: one arrow, straight down.
Each stretched chain pulls it: one tension arrow per chain, both straight up.
At rest, the two tensions together balance the weight.
Three arrows: the weight down, and two tensions up, one per chain.
A punching bag hangs at rest from one vertical chain. Which set of arrows is its correct free-body diagram?
The punching bag hangs at rest. How does the tension in the chain compare with the bag's weight?
A mirror hangs level and at rest from two vertical cords. Which statement about the two tensions is correct?