ps:// Common/TakeT C Search HW#6 Begin Date: 10/15/2017 1200:00 AM .. Due Date:
ID: 1789477 • Letter: P
Question
ps:// Common/TakeT C Search HW#6 Begin Date: 10/15/2017 1200:00 AM .. Due Date: 10/26/2017 12 00 00 AM End Date: 10262017 12 00 00 AM (8%) Problem ll: The speed of a block traveling on a honzor tal frictional surface changes from v.-13 tn s to vr= 10.5 m/s in a distance of d = 8.5 Assignment Status Click here for detailed view 33% Part (a) How long in seconds did it take for the block to slow by this amount, assuming the acceleration is constant? 33% Part (b) If the block has a mass of 1 kg. what is the power supplied to the block by friction? 33% Part (c) what is the coefficient of kinetic friction between the block and surface - ? Grade Summary Potential Submissions Attempts remaining detailed view Problem Status 2 Completed 3 Completed 4 Completed 5 Completed cotanOacos per attempt) atan0 acotanO sin ° Degrees Radians Hint cosh tanh cotanh Subenit I give upl Hints:-deduction per hint Hmts remaining:- Feedback: 0 deduction per feedback 10 Completed l1 Partial 12 Completed 13Explanation / Answer
(A) Applying vf^2 - vi^2 = 2 a d
10.5^2 - 13^2 = 2(a)(8.5)
a = - 3.46 m/s^2
vf = vi + a t
10.5 = 13 - 3.46 t
t = 0.723 sec
(b) Work done = change in KE
= 1 (10.5^2 - 13^2) / 2
= - 29.375 J
power = Work done / time
= 29.375 / 0.723
= 40.6 W
(c) a = - uk g
uk = 0.35
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