Question 6

A car (A) is driving in the positive x-direction and is slowing down.

A second car (B) is driving in the opposite direction and is getting faster.

Which of the following statements is correct?

a) The acceleration of car A is negative, that of car B is positive

b) The acceleration of car A is positive, that of car B is negative

c) The acceleration of both cars is negative

Average: = 42%

Comment:

This item is testing, if students know about negative acceleration. This topic is not treated very carefully by many teachers. So we cannot really expect that all students should know about this.

Next time I would exclude this item.