(10%) Problem 7: A box slides down a plank of length d that makes an angle of 0 with the horizontal, as shown. The kinetic and static coefcients of friction are pk and m ,respectively. [:1 $2 33% Part (a) Enter an expression for the minimum angle at which the box, if initially at rest, will begin to slide 9mm = Pk m g sin(e) X Attempts Remain [:1 & 33% Part (b) Enter an expression for the nonconservative work done by kinetic friction as the block slides down the plank' Assume the box starts from rest, and the angle 9 is large enough that it will slide down the plank. A 33% Part (c) For a plank of any length, at what angle, in degrees, will the nal speed of the box at the bottom of the plank be 0.91 times the nal speed of the box when there is no friction present? Assume pk = 0.29. sin() cos() tan() It ( ) LI 8 9 HOME cotan() asin() acos() l??"J, 4 |T? e atan() acotanO sinh() / * LI 2 3 a cosh() tanh() cotanh() |_T - 0_ END ODegrees Radians '/() BACKSPACE m CLEAR Submit Hint Feedback I give up! Feedback: 0% deduction per feedback. Hints: 0% deduction per hint. Hints remaining: 1 Grade Summary Deductions 0 \"/5 Potential 100% Submissions Attempts remaining: Z (% per attempt) detailed view