When carrying something heavy alone (a couch for example) it is either really heavy or seemingly impossible to lift, but when 2 people on each side lift, it suddenly becomes super light, and I think they have all the weight, making me feel guilty. I recently helped someone move and they said they thought the same. Where does all the weight go?
In: 3
First of all, the other person is taking half the weight, but that’s only part of the story.
When a weight is at the end of a lever, it’s harder to pick up. Try picking up a sledge hammer from the end of the handle, vs the top where the hammer is — it will be easier on the hammer side. Basically, the closer the center of gravity is to the weight’s support, the easier it is to lift because the lever arm is smaller.
So when you try to pick up the couch, most of the weight is far away from you, which makes it more difficult to lift — the other side wants to rotate downward. When you have two people at opposite ends of the couch, the center of gravity of the couch is between the two people, or inside the base (the base being the 4 legs of the people picking up the couch).
If you put both people on the same side of the couch, it will still be very hard to lift because the far side will be at the end of a long lever arm.
The real answer to this needs a picture with force vectors. Hopefully my explanation with just words made some kind of sense.
Latest Answers