For beginning students it is often difficult to understand Newton's second law.1,2 I wrote the following question for a mid‐term examination.

1.
Douglas A.
Kurtze
, “
Teaching Newton's second law—A better way
,”
Phys. Teach.
29
,
350
(Sept.
1991
).
2.
C. Gregory
Hood
, “
Teaching Newton's second law—Another viewpoint
,”
Phys. Teach.
30
,
358
(Sept.
1992
).
3.
www.thefind.com/family/info‐remote‐control‐rc‐flying‐saucer.
This content is only available via PDF.
AAPT members receive access to The Physics Teacher and the American Journal of Physics as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.