drake asked in Science & MathematicsPhysics · 2 months ago

# If two forces are acting on you to result in a zero net force, are there any forces acting on you?

If two balanced forces are acting on you, are those forces really forces? By definition, wouldn’t maybe it be true that’s a force isn’t truly a force if acceleration isn’t happening?

Update:

And I mean if the bodies don’t contract under pressure, too. If there is no movement, then all that is there is atoms “touching” each other. You wouldn’t feel pressure if your skin isn’t being moved out of shape. It would just be atoms next to each other and nothing more.

Update 2:

By contract I mean deformed. A rigid body.

Update 3:

To respond to one of the comments, gravity technically isn’t a force when you consider it to be the result of bodies traveling straight line paths through four dimensional curved spacetime. By Newton’s first and second law of motion, (and Einstein’s revision of the latter), you can only travel in straight lines when the net force is zero. So since gravity is the result of moving in a straight line, there is zero forces involved with gravity. I understand gravity is a fundamental force, however.

Update 4:

I believe my physics book says that scientists don’t know the true answer to this. It’s debatable on whether a force is a force if motion isn’t happening.

Relevance
• 2 months ago

I think the answer is in the question. If there two forces acting on you, then there ARE two forces ACTING on you. If there were to be zero forces working on you, then there would be no forces working on you, but the premise is that; a nullified force is still a force, and if it exists, it's nullification does not eliminate its effects, it just reduces it to a to a tiny fraction of the effect it would normally have. Just my opinion, and maybe I'm wrong.

• Anonymous
2 months ago

You're saying that there is no net force.  Well then, the net force is zero.

Suppose you hollowed out a spherical room at the very center of the Earth, and held back the lava and air-conditioned it.  You would float around in that room as if you were in free-fall in deep space, and (by Einstein's Equivalence Principle) there is no local measurement you could make that would tell you that you're not in free-fall in deep space.  In a Newtonian sense, the Earth would be exerting forces on you, but they would balance out and there would be no net force.

If you were in contact with someone who actually was in freefall in deep space, however, you would see that your clock ran faster than their clock.

• 2 months ago

Concept of force does not require motion.

The branch of mechanics that deals with the analysis of loads acting on physical systems that are in equilibrium with their environment is called statics.

Such systems do not experience an acceleration - they are either at rest, or its center of mass moves at constant velocity.

Statics is essential in civil  engineering.

The assumption of zero acceleration does not mean there are no forces at all, just that forces are in ballance = the resultant force acting on system is zero.

The same applies for torques. In equilibrium

net torque on every part of the system is zero. The net forces equaling zero is called the first condition for equilibrium, and the net torque equaling zero is called the second condition for equilibrium.

• 2 months ago

Bodies always compress under pressure.  The points of contact MUST accelerate.  Only the centre of mass remains motionless in your scenario.  .  The FORCES are non zero but the NET force is zero. Bearing in mind a part of your question you must understand THERE IS NO SUCH THING AS A RIGID BODY.  It is a physical impossibility.  A body must compress, expand, twist or rotate in response to two (or more) forces that do not apply at a single point. Your question is flawed.

• 2 months ago

If F1 and F2 are the only two external forces  acting on an object,  and the forces have equal magnitudes and opposite directions, there are 3 things to consider:

1) The resultant force on the obect is zero, so the centre of mass has zero acceleration.

2) If The forces have the same line of action, then the object in compression or tension.  Except for an ideal 'rigid body', some deformation will occur.

3) If The forces have the differents lines of action, then:

a) the object  will be subject to a torque and acquire angular momentum (rotation);

b) the object will be subject to shear. Except for an ideal 'rigid body', some deformation will occur.

Also, note it is incorrect to say "gravity is the result of moving in a straight line".  Neither Newton nor Einstein said that, and it is wrong.

• 2 months ago

Yes, two of them.  you just said so. Does anything happen though?  no.

• ?
Lv 7
2 months ago

Yes, they are real forces. Gravity doesn't cease to exist just because you're standing on solid ground.

• Rick B
Lv 7
2 months ago

If a force is pushing on my right arm and an equal force is pushing on my left, I feel the pressure of the force, so no, it would not be true to say that there are not any forces acting on me.  Just because I do not move, does not mean there are no forces.