Friction or some force acting on momentum of an object

AI Thread Summary
Friction and air resistance generally decrease the momentum of an object by acting in opposition to its motion. While the absolute value of momentum decreases due to these forces, if the momentum is negative, it can increase. The effect of these forces on momentum also depends on the reference frame; in a moving frame, friction could potentially increase momentum. An example illustrating this is a car accelerating, where friction between the tires and the road propels the car forward, increasing its momentum. Overall, friction typically acts to reduce momentum unless specific conditions alter its effect.
parwana
Messages
182
Reaction score
0
Would forces like friction and air resistance increase momentum or decrease it?

I would think if a force acts on momentum it would decrease the momentum of an object. Is that right?

P= mv

P= Ft
 
Physics news on Phys.org
It depends on the direction of the force with respect to velocity. In the case of friction and air resistance, the absolute value of the momentum will always decrease, yes.

It should be noted that if the momentum is negative, it will actually increase
 
Of course it would decrease it, but this is assuming a certain refrence frame.
If for some reason the refrence frame were moving, then friction could increase momentum.
 
or I guess it could decrease it and then start increasing it.

<<just to confuse you :) >>
 
I am sure you are familiar with friction decreasing momentum. An example of friction inceasing momentum would be the way a car accelerates. The force that pushes the car forward is actually friction from the road on the tyre. The car accelerates and increases its momentum.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Angular momentum conservation on a merry-go-round
Replies
5
Views
2K
Spring momentum conservation problem
Replies
4
Views
2K
Final momentum of box with reflective interior hit by ideal laser
Replies
4
Views
918
Relation between Friction, Velocity, and Acceleration
Replies
16
Views
983
Momentum: instantaneous or average?
Replies
9
Views
1K
Is Linear Momentum Conserved in This Case? (sliding box hits a floor tile)
Replies
2
Views
902
Determining v from momentum / impulse
Replies
2
Views
1K
Friction and an object stopping
Replies
12
Views
3K
Static equilibrium | Uniform sphere on incline | Determining friction
Replies
43
Views
2K
Link between increase in Potential energy and the thermal energy lost
Replies
21
Views
2K

Hot Threads

Recent Insights

Back
Top