- #1
IcyDuck
- 4
- 0
Homework Statement
Two masses ##m_1## and ##m_2## are connected by a massless cord and a pulley, on a rough ramp, tilted at angle ∅ The pulley is massless and frictionless. The coefficient of kinetic friction between the ramp and m1 is ##μ_k.## Derive an expression for ##m_1,## given that ##m_2## accelerates downward with acceleration of magnitude ##a.##
Diagram:
Homework Equations
##F=ma##
##g=9.8 m/s^2##
The Attempt at a Solution
I drew my free body diagrams for each mass.
For ##m_1,## the axes are aligned with the ramp, not the ground. ##m_1g## is broken up into its ##x## and ##y## components: ##m_1gsin∅## and ##m_1gcos∅,## respectively. Tension ##T## is larger than frictional force ##F_f## since the object is accelerating up the ramp despite the frictional force in the opposite direction.
For ##m_2,## the axes are aligned with the ground with the up direction being the positive ##y## direction. The weight ##mg## is larger than the tension ##T## due to its downward acceleration.
I think that the tension will be the same everywhere in the rope, so ##T_{m_1}=T_{m_2}.##
With regard to ##m_1:##
##T=m_2a##
##F_{net}=T-F_f,##
or
##F_{net}=m_2a-μ_km_1gcos∅.##
With regard to ##m_2:##
##F_{net}=m_2g-T,##
or
##F_{net}=m_2g-m_2a.##
That's about as far as I got. It's not much of a start. I don't know what steps I need to take towards isolating ##m_1.##
Last edited: