Understanding Momentum: What Happens When Insufficient Force is Applied?

  • Thread starter Thread starter pallidin
  • Start date Start date
  • Tags Tags
    Momentum
pallidin
Messages
2,207
Reaction score
3
I can't seem to wrap my head around this. Perhaps you can help:

Let's say I've managed to accelerate a mass to 1/2c.
Now, I wish to get that mass going faster, BUT, the newly applied force is not enough to do this.

What then happens to the "insufficient" applied energy? Is it absorbed, reflected, dissipated, etc...?

Thanks
 
Last edited:
Physics news on Phys.org
What do you mean? If you apply a force the object will accelerate and the energy will be equal to the force times the distance.
 
Dale,

Thank you for your interest/reply.

If the force is unable to further accelerate the mass(by virtue of that force being weaker than required to overcome inertia) what happens to the applied force?

It is my understanding(perhaps wrong) that an applied force MUST be sufficient enough to overcome the inertia of the mass or the mass will NOT accelerate.
 
pallidin said:
It is my understanding(perhaps wrong) that an applied force MUST be sufficient enough to overcome the inertia of the mass or the mass will NOT accelerate.
This is a misunderstanding. Any net force, no matter how small, will result in an acceleration. If the force is very small relative to the mass then the acceleration will be correspondingly small, but it will still be there.

You may be thinking of static friction, where you have to apply a force greater than the static friction force in order for there to be a net force so that the object can start moving.
 
OK. Thank you so much.
 
I started reading a National Geographic article related to the Big Bang. It starts these statements: Gazing up at the stars at night, it’s easy to imagine that space goes on forever. But cosmologists know that the universe actually has limits. First, their best models indicate that space and time had a beginning, a subatomic point called a singularity. This point of intense heat and density rapidly ballooned outward. My first reaction was that this is a layman's approximation to...
Thread 'Dirac's integral for the energy-momentum of the gravitational field'
See Dirac's brief treatment of the energy-momentum pseudo-tensor in the attached picture. Dirac is presumably integrating eq. (31.2) over the 4D "hypercylinder" defined by ##T_1 \le x^0 \le T_2## and ##\mathbf{|x|} \le R##, where ##R## is sufficiently large to include all the matter-energy fields in the system. Then \begin{align} 0 &= \int_V \left[ ({t_\mu}^\nu + T_\mu^\nu)\sqrt{-g}\, \right]_{,\nu} d^4 x = \int_{\partial V} ({t_\mu}^\nu + T_\mu^\nu)\sqrt{-g} \, dS_\nu \nonumber\\ &= \left(...
In Philippe G. Ciarlet's book 'An introduction to differential geometry', He gives the integrability conditions of the differential equations like this: $$ \partial_{i} F_{lj}=L^p_{ij} F_{lp},\,\,\,F_{ij}(x_0)=F^0_{ij}. $$ The integrability conditions for the existence of a global solution ##F_{lj}## is: $$ R^i_{jkl}\equiv\partial_k L^i_{jl}-\partial_l L^i_{jk}+L^h_{jl} L^i_{hk}-L^h_{jk} L^i_{hl}=0 $$ Then from the equation: $$\nabla_b e_a= \Gamma^c_{ab} e_c$$ Using cartesian basis ## e_I...
Back
Top