Help! I don\'t understand this at all! I need to see it worked out! Here\'s a li

Question

Help! I don't understand this at all! I need to see it worked out! Here's a link to the problem if the picture below does not appear for you: http://smg.photobucket.com/user/nloup1/media/6fc3c149-b9ab-4118-baef-4244b084e716_zps9be30ff9.jpg.html?sort=3&o=0

A glass marble is allowed to roll down a curved ramp so that it collides with the end of a wooden meter stick that is suspended from a frictionless pivot at point p, as shown below. The marble has mass m=5.40 g and radius r=0.80 cm. The meter stick has mass M=0.160 kg and length D=1.0 m.

Explanation / Answer

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a) TE1 = m*g*h.........

TE2 = KEr + KEt = 0.5*(2/5)*m*r^2*w^2 + 0.5*m*Vcm^2

TE2 = 0.5*(2/5)*m*r^2*Vcm^2/r^2 + 0.5*m*Vcm^2

TE2 = 0.5*(7/5)*m*Vcm^2

TE2 = TE1

m*g*h = 0.5*(7/5)*m*V^2

Vcm = sqrt(2*(5/7)*g*h) = (2*(5/7)*9.8*2.5)^.5 = 5.92 m/s

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b) L1 = m*Vcm*D = 0.0054*5.92*1 = 31.97*10^-3 kg m^2 /s

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c)
final MOI I2= (1/3)*M*D^2 + m*D^2 = (M/3 + m)D^2 = ((0.16/3)+0.0054)*1 =

58.73*10^-3 kg m^2

final angular momentum L2 = I2*W

according to law of conservation of angular momentum

L2 =L1

W = 31.97e?3/58.73e?3 = 544.36e?3 rad/s

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d) KE = (M+m)*g*H

0.5*I2*W^2 = (M+m)*g*H

0.5*58.73*10^-3*(544.36*10^-3)^2 = (0.16+0.0054)*9.8*H

H = 5.37*10^-3 m

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