Does it take more energy to open a door that’s closed or one that’s swinging shut?

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Does the answer change depending on if the door is push / pull?

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2 Answers

Anonymous 0 Comments

it depends.

With swinging door, you need energy to overcome the momentum of the door since is moving in the opposite way from where you need it. This will depend on the weight of the door, and how fast it is swinging.

With closed door, you need energy to overcome the friction between door and door frame. that depends on materials and how tight the frame is. Some doors are wedged shut.

Also, wind blowing through the door or against the door can change the effort needed.

If this is a physics homework question, read the rest of the assignment or class materials, maybe you are told to ignore friction, and I pretty sure there is no wind. If that’s the case, the u/chickenologist answer applies.

Anonymous 0 Comments

If it’s closed and locked, that’s your winner right there.
If we’re assuming all else is the same, then to open it from rest means you apply enough force to make the hinge rotate outward. Let’s can that amount of force X. If it’s swinging shut, you first have to apply enough force to bring it to rest. Let’s call that amount of force Y. You can probably see that whatever actual amount X or Y might be, X+Y will be greater than just X.