(10%) Problem 7: A box slides down a plank of length d that makes an angle of 0 with the horizontal as shown. Mk is the kinetic coefficient of friction and us is the static coefficient of friction. d 4 33% Part (a) Enter an expression for the minimum angle 0 (in degrees) the box will begin to slide. A 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 0 is large enough that it will move down the plank. 33% Part (c) For a plank of any length, at what angle 0 (in degrees) will the final speed of the box at the bottom of the plank be 0.65 times the final speed of the box when there is no friction present? Assume Mk = 0.34. 0 = 1 sin( cos() tan() JT. 7 8 9 HOME cotan() asin() acos() E A 4 5 6 atan() acotan() sinh() 2 3 cosh() tanh() cotanh() + END O Degrees O Radians VO BACKSPACE DEL CLEAR Submit Hint Feedback I give up