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~christina~
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[SOLVED] Atwood Machine
A pulley which is mounted in horizontal frictionless bearings, has a radius of 5.00 cm. One block has mass M = 500 g and the other has mass m = 460 g. When released from rest, the more massive block falls 75 cm in 5.00 s (without the cord slipping on the pulley.)
(a) What is the magnitude of the blocks’ acceleration? What is the tension in the cord that supports
(b) the more massive block and
(c) the less massive block?
(d) What are the magnitude and direction of the pulley’s angular acceleration?
(e) What is its rotational inertia?
(f) Find the rotational kinetic energy after 5.00 s.
http://img264.imageshack.us/img264/6785/atwoodue6.th.jpg
[tex] K_i + U_i = K_f + U_f [/tex]
[tex] v= R\omega [/tex]
[tex]a_t= r\alpha[/tex]
know that:
r= 5.00cm=> 0.05m
M= 500g=> 0.5kg
m= 460g = 0.46g
h= 75cm=> 0.75m
I'm not sure exactly how to get this at all.
notation confuses me somewhat for rotation motion
I was just reading the chapter today since we just learned this the other day.
a) What is magnitude of block's acceleration?
I was thinking about using Newton's second law with the forces that are on the blocks.
[tex]\sum F_{y}= m_2g - T= m_2a_y [/tex]
[tex]\sum F_{y}= T- m_1g = m_1ay [/tex]
m_2g - m_1g = a_y(m_1 + m_2)
a_y= g [(m_2 - m_1)/ (m_1 + m_2)]
However I don't think I'm supposed to get the acceleration this way...since they give the radius and the time...I don't know how to incorperate the time and the radius if I need to.
Help please.
Homework Statement
A pulley which is mounted in horizontal frictionless bearings, has a radius of 5.00 cm. One block has mass M = 500 g and the other has mass m = 460 g. When released from rest, the more massive block falls 75 cm in 5.00 s (without the cord slipping on the pulley.)
(a) What is the magnitude of the blocks’ acceleration? What is the tension in the cord that supports
(b) the more massive block and
(c) the less massive block?
(d) What are the magnitude and direction of the pulley’s angular acceleration?
(e) What is its rotational inertia?
(f) Find the rotational kinetic energy after 5.00 s.
http://img264.imageshack.us/img264/6785/atwoodue6.th.jpg
Homework Equations
[tex] K_i + U_i = K_f + U_f [/tex]
[tex] v= R\omega [/tex]
[tex]a_t= r\alpha[/tex]
The Attempt at a Solution
know that:
r= 5.00cm=> 0.05m
M= 500g=> 0.5kg
m= 460g = 0.46g
h= 75cm=> 0.75m
I'm not sure exactly how to get this at all.
notation confuses me somewhat for rotation motion
I was just reading the chapter today since we just learned this the other day.
a) What is magnitude of block's acceleration?
I was thinking about using Newton's second law with the forces that are on the blocks.
[tex]\sum F_{y}= m_2g - T= m_2a_y [/tex]
[tex]\sum F_{y}= T- m_1g = m_1ay [/tex]
m_2g - m_1g = a_y(m_1 + m_2)
a_y= g [(m_2 - m_1)/ (m_1 + m_2)]
However I don't think I'm supposed to get the acceleration this way...since they give the radius and the time...I don't know how to incorperate the time and the radius if I need to.
Help please.
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