Answer and Explanation:
The motion of the viper is circular and it completes a semi- circle forming an arc and then retraces its path back.
Thus the force experienced by the bug is centripetal force thus centripetal acceleration and in the absence of this force the bug will get dislodged.
This centripetal force is mainly provided by the static friction between the blades and the bug.
When the wipers are moving with high velocity when turned on, larger centripetal force is required to keep the bug moving with the wiper on the arc than at low setting.
Thus there are more chances for the bug to be dislodged at higher setting than at low setting.
