hw_5 Solution

# hw_5 Solution - Problems Set 5 Chapter 8 10 We choose that...

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Problems Set 5 Chapter 8 10.) We choose that the zero point of the potential energy is the point at which the block comes to rest, when the spring is compressed. We are dealing with only conservative forces, so that the mechanical energy in the beginning is equal to the mechanical energy in the end. The energies are kinetic, gravitational potential and spring potential: Then, we solve for d, and find 24.) a.) The decrease in gravitational potential energy, will result in an increase in kinetic energy. Then we just solve for the speed. Similarly for v c , we just replace h b with h c , v c =7.67 m/s. b.) The net work done from moving from A to C is 31.) The loss of mechanical energy from the beginning to the end is due to the force of friction. Therefore, we have if EE = i g i s g f sf KUUKUU ++=++ 2 1 2 0( )si n 000 mg d x kx q + + +=++ 2 2 sin kx dx mg q =- fifi UUKK -=- 22 11 2 1 2 0 abba abb mg h mg h m v mv mg h mg h mv 2 2 () 2 2(9.8)( 5 3.20) 5.9 4/ b ab b b b v g h gh v g hh v v ms = 5.00(9.8)(5.0 0 2.00) 147 ac W W WJ =

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We know that the force of friction is just proportional to the normal force on block 1, so we have We just solve for the velocity. 33.) a.) The block starts with kinetic energy and comes to rest. We have b.) We set the zero of the potential energy to be at the place where the block starts its motion. Then after traveling a distance, x, along the plane, the change in the potential energy is c.) The change in mechanical energy is from the energy lost to friction. The change in mechanical energy is We solve for the force.
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## This note was uploaded on 07/28/2010 for the course PHYS 207 taught by Professor Winnokur during the Fall '06 term at University of Wisconsin.

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hw_5 Solution - Problems Set 5 Chapter 8 10 We choose that...

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