Physics Help! Connected objects..?

Question

Consider a force of 62.4N pulling 3 blocks of identical masses, where each mass is 1kg, along a rough horizontal surface. The coefficient of kinetic friction is 0.8. The accel of gravity is 9.81m/s^2.
- What is the acceleration?


-The tension of the strings are T1 and T2. The equation of motion m2 is given by what ?
a) T1-μ m2g = m2a
b) T1-T2 + μ m2g - μ m1g = m2a
c) T1 + μ m2g = m2a
d) T1- T2 - μ m2g = m2a
e) T1 - T2 + μ m2g = m2a
f) T1 + T2 - μ m2g = m2a
g) T1 + T2 - μ m2g - μ m1g = m2a.

Please Help, I thought I figured it out - but was wrong..thanks

Answer 1

-The tension of the strings are T1 and T2
T1-μ*m2*g = m2*a
T2-T1- μ*m1*g = m1*a
62.4-T2- μ*m3g = m3*a

all of the masses =1

μ=0.8

T1-7.848= a
T2-T1- 7.848 = a
62.4-T2- 7.848= a

46.704-T1=2*a
T1=46.704-2*a
46.704-7.848= 3*a
38.856/3=a

a=12.952 m/s^2
T1=20.8
T2=41.6

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