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Unformatted text preview: lenoir (wml297) – oldhomework 14 – Turner – (58220) 1 This print-out should have 16 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 3) 10.0 points A 2 . 3 kg particle moves along the x axis under the influence of a single conservative force. If the work done on the particle is 118 J as it moves from x 1 = 3 m to x 2 = 6 m, find the change in its kinetic energy. Correct answer: 118 J. Explanation: The change in the kinetic energy is equal to the work done: Δ K = W = 118 J . 002 (part 2 of 3) 10.0 points Find the change in its potential energy. Correct answer:- 118 J. Explanation: Since Δ K + Δ U = 0 , then Δ U =- Δ K =- 118 J . 003 (part 3 of 3) 10.0 points Find its speed at x 2 = 6 m if it starts from rest. Correct answer: 10 . 1296 m / s. Explanation: Using K = m ( v 2 end- v 2 init ) 2 we obtain v = radicalbigg 2Δ K m = radicalBigg 2(118 J) 2 . 3 kg = 10 . 1296 m / s . 004 10.0 points A block of mass m slides on a horizontal frictionless table with an initial speed v . It then compresses a spring of force constant k and is brought to rest. The acceleration of gravity is 9 . 8 m / s 2 . v m k m μ = 0 How much is the spring compressed x from its natural length? 1. x = v 2 2 m 2. x = v radicalbigg m k correct 3. x = v m k g 4. x = v radicalBigg k mg 5. x = v k g m 6. x = v radicalbigg k m 7. x = v 2 2 g 8. x = v radicalbigg mg k 9. x = v mk g 10. x = v mg k Explanation: Total energy is conserved (no friction). The spring is compressed by a distance x from its natural length, so 1 2 mv 2 = E i = E f = 1 2 k x 2 , or x 2 = m k v 2 , therefore x = v radicalbigg m k . lenoir (wml297) – oldhomework 14 – Turner – (58220) 2 Anyone who checks to see if the units are correct should get this problem correct. 005 10.0 points A bead slides without friction around a loop- the-loop. The bead is released from a height of 16 m from the bottom of the loop-the-loop which has a radius 5 m....
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This note was uploaded on 04/15/2010 for the course PHY 12343 taught by Professor Turner during the Spring '10 term at University of Texas.
- Spring '10