- #1
frozenguy
- 192
- 0
Two boxes connected with a pulley, one hanging *updated*
There is a Mass (m1) on a table. The coefficient of friction between the table and m1 is 0.18. The second mass (m2) is hanging, suspended by a string around a pulley (m3) attached to m1. The pulley has a radius (R) and is considered a solid cylinder.
m1=3.5[kg]
m2=2.8[kg]
m3=1.9[kg]
R=0.089[m]
Find:
a) alpha of the pulley
b.)Ft1
c.)Ft2
d.)omega @ (6.9)
I for solid cylinder = (1/2)M2R2
Fnet=ma
Torquenet=I*alpha
alpha=a/R
I drew a torque fbd for the pulley, I found I for the pulley, I drew fbd's for the boxes, got my equations like
m1-->
X) Ft1-Ff=m1a
Y) Fn-Fg=0
Fn=m1g
Ft1=m1a+Ff
Ft1=m1a+Mew*m1*gm2--->
Y) Ft2-Fg=m2(-a)
Ft2=-m2a+m2g
and finally
Torquenet=I*alpha so
Torque1=R*sin(90)*Ft1 = R*Ft1 (k)
Torque2=R*sin(90)*Ft2 = R*Ft2 (-k)
==>R*Ft1-R*Ft2=I*alpha
and alpha= a/R
So
R*(m1a+Mew*m1*g)-R*(-m2a+m2g)=((1/2)M3R2)*(a/R)
That equation just has one uknown --> a
For a i got 3.97[m/s2]
For alpha I am getting like 44 [rads/s2] and others are getting about about 16 [rad/s2]
Can someone spot what, if anything, I'm doing something wrong?EDIT: Sorry for the mistakes..
Homework Statement
There is a Mass (m1) on a table. The coefficient of friction between the table and m1 is 0.18. The second mass (m2) is hanging, suspended by a string around a pulley (m3) attached to m1. The pulley has a radius (R) and is considered a solid cylinder.
m1=3.5[kg]
m2=2.8[kg]
m3=1.9[kg]
R=0.089[m]
Find:
a) alpha of the pulley
b.)Ft1
c.)Ft2
d.)omega @ (6.9
Homework Equations
I for solid cylinder = (1/2)M2R2
Fnet=ma
Torquenet=I*alpha
alpha=a/R
The Attempt at a Solution
I drew a torque fbd for the pulley, I found I for the pulley, I drew fbd's for the boxes, got my equations like
m1-->
X) Ft1-Ff=m1a
Y) Fn-Fg=0
Fn=m1g
Ft1=m1a+Ff
Ft1=m1a+Mew*m1*gm2--->
Y) Ft2-Fg=m2(-a)
Ft2=-m2a+m2g
and finally
Torquenet=I*alpha so
Torque1=R*sin(90)*Ft1 = R*Ft1 (k)
Torque2=R*sin(90)*Ft2 = R*Ft2 (-k)
==>R*Ft1-R*Ft2=I*alpha
and alpha= a/R
So
R*(m1a+Mew*m1*g)-R*(-m2a+m2g)=((1/2)M3R2)*(a/R)
That equation just has one uknown --> a
For a i got 3.97[m/s2]
For alpha I am getting like 44 [rads/s2] and others are getting about about 16 [rad/s2]
Can someone spot what, if anything, I'm doing something wrong?EDIT: Sorry for the mistakes..
Last edited: