This may not be a good advice about AP Physics 1. AP Physics 1 covers more materials than AP Physics C Mechanics. Although calculus is not required, students are expected to understand and explain physics phenomena in AP Physics 1 instead of plugging and chugging numbers. Only 4% of students scored 5 on AP Physics 1 while 27% of students scored 5 on AP Physics C Mechanics. And more than 60% of students received scores of 2 & 1 in AP Physics 1. Only 23% of students received scores of 2 & 1 in AP Physics C Mechanics.
I guess students received low scores in AP Physics 1 because of wrong teacher expectation.
http://www.totalregistration.net/AP-Exam-Registration-Service/2015-AP-Exam-Score-Distributions.php