31. A man slides down on a telegraphic pole with an acceleration equal to one-fourth of acceleration due to gravity. The frictional force between man and pole is equal to in terms of man's weight w
a) \( \frac{w}{4} \)
b) \( \frac{w}{2} \)
c) \( \frac{3 w}{4} \)
d) \( W \)