Mastering Physics-Fall-2 Hor MasteringPhysics: HW#7 Microsoft Edge HW#7 Question
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Mastering Physics-Fall-2 Hor MasteringPhysics: HW#7 Microsoft Edge HW#7 Question 8 session.masteringphysics.com/myct/iternView?assignmentProblemID-80020820 « previous | 8 of 11 I next MasteringPhysics Question 8 3 My Courses Part A You are a member of an alpine rescue team and must get a box of supplies, with mass 2.90 kg, up an incline of constant slope angle 30.0 so that it reaches a stranded skier who is a vertical distance 2.50 m above the bottom of the incline. There is some friction present; the kinetic coefficient of friction is 6.00x10. Since you can't walk up the incline, you give the box a push that gives it an initial velocity; then the box slides up the incline, slowing down under the foroes of friction and gravity. Take acceleration due to gravity to be 9.81 Use the work-energy theorem to calculate the minimum speed w that you must give the box at the bottom of the incline so that it will reach the skier. Course Home Assignments Scores eText Express your answer numerically, in meters per second. Hints Study Area Help 7.18 m s Submit My Answers Give Up Incorrect; Try Again; 4 attempts remaining You are on the right track. Be sure to include the distance over which friction acts when calculating the work done by friction. Continue 11:01 AM Type here to search 10/15/2017Explanation / Answer
Applying work - energy theorem,
Work done by gravity + work done by friction +work done by normal = change in KE
- m g h + (- f . d) + 0 = 0 - m v0^2 /2
{ f = uk N = uk m g cos30 and d = h/ sin30}
- m gh - uk m g h / tan30 = m v0^2 /2
- 9.81 x 2.50 ( 1 + 0.06/tan30) = v0^2 /2
v0 = 7.36 m/s