What is the acceleration of the minimum mass needed to prevent slipping?

[SherBear]

Figure shows a block of mass resting on a slope. The block has coefficients of friction and with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging block of mass 2.0 kg.
i got this first one: What is the minimum mass that will stick and not slip?

1.83 kg
Correct

But can't get the second part:
If this minimum mass is nudged ever so slightly, it will start being pulled up the incline. What acceleration will it have?

Thank you! :)

 

[ehild]

Figure shows a block of mass resting on a slope. The block has coefficients of friction and with the surface.

Correct the sentence in red please. What are the coefficients of friction?

ehild

 

[PeterO]

Figure shows a block of mass resting on a slope. The block has coefficients of friction and with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging block of mass 2.0 kg.
i got this first one: What is the minimum mass that will stick and not slip?

1.83 kg
Correct

But can't get the second part:
If this minimum mass is nudged ever so slightly, it will start being pulled up the incline. What acceleration will it have?

Thank you! :)

Once the block starts moving, the coefficient of friction is then the kinetic coefficient, which will mean a smaller friction. Thus there is a net force up the slope [and down on the hanging mass] which causes the system to accelerate.

 

[SherBear]

I'm really sorry about that ehild! The mu(s) is .8 but the mu(k) which I assume we use on this problem because it's moving therefore kinetic is .5 =-)

 

[SherBear]

Once the block starts moving, the coefficient of friction is then the kinetic coefficient, which will mean a smaller friction. Thus there is a net force up the slope [and down on the hanging mass] which causes the system to accelerate.

Thank you Peter!

 

[ehild]

I'm really sorry about that ehild! The mu(s) is .8 but the mu(k) which I assume we use on this problem because it's moving therefore kinetic is .5 =-)

Everything is clear then. Can you solve the second part or still need help?

ehild

 

[SherBear]

Everything is clear then. Can you solve the second part or still need help?

ehild

Yes, it's clear. Thank you ehild! :)