In problem 15 if a motor-cyclist passes over the bridge at 18 ms^(-1), atb which point will the reaction become equal to zero ?

In problem 15 if a motor-cyclist passes over the bridge at 18 ms^(-1),

1.	In problem 15 if a motor-cyclist passes over the bridge at 18 ms^(-1), atb which point will the reaction become equal to zero ?
Answer» ANSWER :`56^(@) 34'`