As shown in Figure P8.20, a green bead of mass m = g slides along a straight wire. The length of the wire from point A to point B is m, and point A is m higher than point B. A constant friction force of magnitude N acts on the bead.
(a) If the bead is released from rest at point A, what is its speed at point B?
(b) A red bead of mass 25 g slides along a curved wire, subject to a friction force with the same constant magnitude as that on the green bead. If the green and red beads are released simultaneously from rest at point A, which bead reaches point B with a higher speed? Explain