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Unformatted text preview: Engineering Mechanics - Dynamics Chapter 13 determine the distance both blocks slide on the smooth surface before they begin to separate.
What is their velocity at this instant?
Block A: −k( x − d) − N = mA aA Block B: N = mB aB Since a A = aB = a,
a= N= k( d − x)
mA + mB
kmB ( d − x)
mA + mB Separation occurs when
N=0 or x=d d v
⌠ k( d − x)
⎮ v dv = ⎮
⎮ mA + mB
⎜d d −
mA + mB ⎝
⎠ 2 v= kd
mA + mB Problem 13-50
Block A has a mass mA and is attached to a spring having a stiffness k and unstretched length l0. If
another block B , having a mass mB is pressed against A so that the spring deforms a distance d, show
that for separation to occur it is necessary that d > 2μk g(mA+mB)/k, where μk is the coefficient of
kinetic friction between the blocks and the ground. Also, what is the distance the blocks slide on the
surface before they separate?
Solution: Block A: −k( x − d) − N − μ k mA g = mA aA
Block B: N − μ k mB g = mB aB 182 ...
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This note was uploaded on 08/16/2011 for the course EGN 3321 taught by Professor Christianfeldt during the Spring '08 term at University of Central Florida.
- Spring '08