Physics_1112__Spring_2009__Co_op_7__Work___Energy

# Physics_1112__Spring_2009__Co_op_7__Work___Energy - (d Does...

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Name:__________________ Partners:______________________________ 1 Physics 1112 Cooperative Problems Week 7: Work & Energy 1. A sliding 2.5-kg block collides with one end of a horizontal massless spring that has the other end fixed to a wall and whose spring constant N/m 320 = k . The block compresses the spring a maximum distance of 7.5 cm from its relaxed length. The coefficients of static and kinetic friction between the block and the horizontal surface are 0.40 and 0.25, respectively. (a) Draw a FBD for the block when it is in contact with the spring. Find the work done by the spring on the block as the block slows and comes (perhaps momentarily) to rest. Is it positive or negative? (b) How much mechanical energy is dissipated by friction while the block is being brought to rest by the spring? (c) What was the speed of the block when it hit the spring?

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Unformatted text preview: (d) Does the block remain at rest or does the spring send it sliding back to the left? Explain. 2 2. An object of mass M is released from rest from a point P on the frictionless track shown. P is located a height h from the bottom of the track. (a) What is the object’s speed v at point Q (top of the loop) as a function of h ? (b) Draw a free-body diagram for the object at point Q. (c) What is the radial acceleration of the object at point Q given its speed computed in (a)? (d) There is a mininum value of h such that the object remains in contact with the track all the way around the circle. If the object is released from this height, what is the normal force on the object at Q? (e) What is the minimum value of h so that the object completes the loop without losing contact with the track?...
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## This note was uploaded on 12/25/2009 for the course PHYS 1112 taught by Professor Leclair,a during the Spring '07 term at Cornell.

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Physics_1112__Spring_2009__Co_op_7__Work___Energy - (d Does...

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