can someone please help me answer this question ?

Answer:
b 60 N force
Explanation:
The change in the momentum is given by the force•distance from the attached point. We don't have any distance, but apparently, the stick forces are being applied in each quarter of the stick, so let's use fractions of 4 to solve it:
150 N:
150•1/4 = 37.5
30 N:
30•2/4 = 30•1/2 = 15
60 N:
60•3/4 = 45
40 N:
40•4/4 = 40•1 = 40