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Sagekilla
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Homework Statement
Find the the acceleration, a[/i, and the Tension, T, in the system shown below if (a) m1 = 5 kg and (b) m1 = 2 kg. assume the coefficient of kinetic fricton on the incline plane is µk = 0.1.
Other relevant information:
Mass 1 is a 5 or 2 kg block on a 30 degree incline plane (based so that Fy is Fsin(30) ) connected to a massless rope that holds Mass 2, a 5 kg block, over a pulley.
Homework Equations
Ff = (µk)(Fn)
w = mg (acceleration due to gravity is assumed to be 10 m/s^2 for easy calculation according to the professor)
Fnet = ma
The Attempt at a Solution
I solved for the weight of mass 1 as being:
m1 = 5 kg: W = 50 N * sin(30) = 25 N
m2 = 2 kg: W = 20 N * sin(30) = 10 N
And found force of friction:
Ff = 0.1 * 25 N = 2.5 N
The weight of block m2:
w = 10 m/s^2 * 5 kg = 50 N
I tried creating a FBD for block m1, where the following forces were applied:
W = 25 N
Fn = 25 N
Ff = 2.5 N
F = Wm2 (Wm2 = 50 N)
And a FBD for block m2, where:
W = 50 N
Except, I'm confused where to go from here now. I know I have to calculate tension still. I'm thinking that the total force being applied on m1 according to Newton's 2nd Law is:
Fnet = ma - Ff = 50 N - 2.5 N = 47.5 N
And acceleration is: a = 47.5 N / 5 kg = 9.5 m/s^2
2nd attempt:
I know Fnet = ma - T. and Fnet is not 0 N, it's 50 N. Since the rope is massless the tension is 2T = 100 N.I therefore arrive at the following answers of:
a = 9.5 m/s^2
T = 100 NDoes this look right?
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