(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A block of mass m1 is placed on an inclined plane with slope angle a and is connected to a second hanging block of mass m2 by a cord passing over a small frictionless pulley the coefficient of kinetic friction is uk the system is released from rest with block m2 dropping a distance h.

given m1, a, h, m2, uk

calc the work due to each of the forces on block 1 in moving h

calc the work due to each of the forces on block 2 in moving h

calc the total work on the sys and final speed of the blocks

2. Relevant equations

w = F*d

3. The attempt at a solution

http://i.imgur.com/IxtPw.png

for block1

Wg = -h*mg*sin a

Wt1 = hT

Wn=0

Wff = -h*uk*mg*cos a

Wtot = hT - *mg*sin a - h*uk*mg*cos a

for block2

Wg = mgh

Wt = -hT

Wtot = mgh - hT

hT - *mg*sin a - h*uk*mg*cos a + mgh - hT = 1/2*m*Vf^2 + 1/2*m2*Vf^2 - 0 (start from rest)

sqrt( 2/(m1+m2) * (mg*sin a - h*uk*mg*cos a + mgh)) = Vf

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blocks a, b, c are connected as shown. block a,b,c have same mass m and coefficient of kinetic friction between each block and the surface is uk. block c descends with constant velocity. use 30 for angle of incline. given m h uk determine

work due to forces on A moving h

work due to forces on B moving h

work due to forces on C moving h

solve for uk in terms of the other givens for the system to move at constant speed

http://i.imgur.com/DtwxJ.png

block A

Wff= -uk*mg*h

Wt= T1*h

block B

Wt2 = T2*h

Wg = -mg*sin a*h

Wff= -uk*mg*cos a * h

Wt1 = -T1*h

wtot = T2*h - mg*sin a * h - uk*mg*cos a * h - T1* h

block C

Wg = mg*h

Wt2 = -T2*h

Wtot = mg*h - T2*h

T1*h - uk*mg*h + T2*h - mg*sin a * h - uk* mg* cos a * h - T1*h + mg*h - T2*h = 0(constant speed implies vf v0 are the same meaning no change in kinetic energy right??)

-uk*mg*h - uk*mg*cos a * h = mg*sin a * h - mg*h

-uk - uk*cos a = sin a - 1

-uk(1 + cos a) = sin a - 1

uk = - (sin a - 1/ (1+cos a))

uk = 1/2 / (2+sqrt(3))/2

uk = 1/(2+sqrt(3))

want to be sure im not doing anything horribly wrong thanks for any help.

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# Homework Help: Inclined plane work

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