https//edugen wiley...O wyptus Cutnell, Physics, 10e GENERAL PHYSICS (PHYS 2001/
ID: 1875360 • Letter: H
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https//edugen wiley...O wyptus Cutnell, Physics, 10e GENERAL PHYSICS (PHYS 2001/2002) Assignment Gradebook ORION Downloadable eTextbook gnment FULL SCREEN PRINTER VERSION NEXT Chapter 06, Problem 35 A 50.4-kg skateboarder starts out with a speed of 1.70 m/s. He does 113 J of work on himself by pushing with his feet against the ground. In addition, friction does -254 J of work on him. In both cases, the forces doing the work are non- conservative. The final speed of the skateboarder is 8.83 m/s. (a) Calculate the change (PE - PEo) in the gravitational potential energy. (b) How much has the vertical height of the skater changed? Give the absolute value. (a) Number Units (b) Number Units LINK TO TEXTLINK TO TEXT Question Attempts: Unlimited SURNIT m SAVE FOR LATER SUBMIT ANSWER Version 4.Explanation / Answer
Initial potential energy PE0 = m*g*h0
initial kinetic energy KE0 = (1/2)*m*v0^2
final potential energy PEf = 0
final kinetic energy KEf = (1/2)*m*vf^2
work done by skate boarder = WB= 113 J
work done by friction Wf = -254 J
Wtot = dKE
Wg + WB + Wf = KEf - KE0
(PE0 - PEf) + 113 - 254 = (1/2)*50.4*(8.85^2-1.7^2)
PE0 - PEf = 2042 J
PEf - PE0 = -2042 J <<<<------ANSWER
part(b)
PEf - PE0 = m*g*(hf - h0)
-2042 = 50.4*9.8*(0 - h0)
h0 = 4.13 m <<<<------ANSWER
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