B Push from a Narrow Base vs Wide Base

[FizicsAM]

Hello!

When moving an object, how do you describe the changes when you push from a narrow base vs a wide base? For example, say you push something heavy with your palm vs your index finger. It feels easier to push from a palm rather than a finger even if the force from my arm is the same but I'm not sure what's going on from a physics standpoint.

Another way to think about it is a narrow column vs a wider column to support a roof.

 

[Merlin3189]

Pressure. ie Force per unit area.

 

[FizicsAM]

Can you elaborate please?

 

[etotheipi]

Why is it easier to cut through butter with a sharp knife as opposed to with a broader block of wood? Imagine that you push with the same force in each case; what does your intuition tell you?

 

[Merlin3189]

You mentioned pushing with the palm of your hand or the tip of your finger.
What is the area of your hand? Mine is about $50 cm^2$
The area of your finger tip? Mine about $1 cm^2$
So whatever force I need to push, is spread over 50x as much area with my hand as with my finger.
The finger pressure is 50x as big for the same force.

 

[Lnewqban]

...
When moving an object, how do you describe the changes when you push from a narrow base vs a wide base?...

Could you explain what narrow or wide base means to you?
What type of changes do you refer to?

 

[A.T.]

For example, say you push something heavy with your palm vs your index finger. It feels easier to push from a palm rather than a finger even if the force from my arm is the same but I'm not sure what's going on from a physics standpoint.

Part of it is pressure as already explained. The other part is that for pushing with the finger, you have to lock your finger joints using muscle forces, which act over rather short lever arms at these joints.