(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

An object with a mass of 10 kg (this mass is m1) rests on a horizontal table and is connected to a cable that passes over a pulley and is then fastened to a hanging object with mass of 4.0 kg (this mass is m2). The coefficient

of static friction between m1 and the horizontal surface

is 0.50, and the coefficient of kinetic friction is 0.30. If the system is set in motion with m2 moving

downward, what will be the acceleration of the system?

2. Relevant equations

m1 = mass one

m2 = mass two

T = tension

μ = coefficient of friction

g = gravity

a = acceleration

R = normal reaction

I got this helpful hint at another site, but I still can't figure it out...

For m2:

m2 g - T = m2 a ...(1)

Resolving horizontally and vertically for m1:

T - μR = m1 a ...(2)

R = m1 g ...(3)

Substitute for R from (3) in (2):

T - μm1 g = m1 a ...(4)

Add (1) & (4):

(m2 - μm1)g = (m1 + m2)a

a = (m2 - μm1)g / (m1 + m2)

= (4 - 0.3 * 10)g / (10 + 4)

= g / 14

= 0.701 m/s.

3. The attempt at a solution

And this is where I run into the problem. I'm not sure what to do, even with the helpful hint provided on another site.

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# Homework Help: I'm stuck! Not sure where to go. Help!

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