Question
Question: A small block of mass m is released from rest from point D and slides down DGF and reaches the point...
A small block of mass m is released from rest from point D and slides down DGF and reaches the point F with speed vF. The coefficient of kinetic friction between block and both the surfaces DG and GF is μ, the velocity vF is

A
2g(y−x)
B
2g(y−μx)
C
2gy
D
2g(y2+x2)
Answer
2g(y−μx)
Explanation
Solution
Here mgy – 21 mvF2 = f2s + f2s2
i.e., 21 mvF2 = mgy - μmg cos βx1 - μmg cos γs2
or 21 vF2 = g (y− s1μx1 s1− s2μx2 s2)
or vF = 2g(y−μx)