A 0.8 kg bead slides on a curved wire, starting from rest at point A as shown in the figure.
The segment from A to B is frictionless, and
the segment from B to C is rough. The point
A is at height 7.1 m and the point C is at
height 2.5 m with respect to point B.

Find the speed of the bead at B. The acceleration due to gravity is 9.8 m/s2
Answer in units of m/s.

If the bead comes to rest at C, find the change
in mechanical energy due to friction as it
moves from B to C.
Answer in units of J.