Nearly all physics instructors recognize the instructional value of force diagrams, and this journal has published several collections of exercises to improve student skill in this area.1–4 Yet some instructors worry that too few students perceive the conceptual and problem-solving utility of force diagrams,4–6 and over recent years a rich variety of approaches has been proposed to add value to force diagrams. Suggestions include strategies for identifying candidate forces,6,7 emphasizing the distinction between “contact” and “noncontact” forces,5,8 and the use of computer-based tutorials.9,10 Instructors have suggested a variety of conventions for constructing force diagrams, including approaches to arrow placement and orientation2,11–13 and proposed notations for locating forces or marking action-reaction force pairs.8,11,14,15

1.
J. E.
Court
, “
Free-body diagrams
,”
Phys. Teach.
31
,
104
108
(Feb.
1993
).
2.
J. E.
Court
, “
Free-body diagrams revisited—I
,”
Phys. Teach.
37
,
427
433
(Oct.
1999
).
3.
J. E.
Court
, “
Free-body diagrams revisited—II
,”
Phys. Teach.
37
,
490
495
(Nov.
1999
).
4.
K.
Fisher
, “
Exercises in drawing and utilizing free-body diagrams
,”
Phys. Teach.
37
,
434
435
(Oct.
1999
).
5.
R.
Newburgh
, “
Force diagrams: How? and why?
Phys. Teach.
32
,
352
(Sept.
1994
).
6.
D. Rosengrant, A. Van Heuvelen, and E. Etkina, “Free-body diagrams: Necessary or sufficient?” Paper presented at the Physics Education Research Conference, Sacramento, CA (1994). From web.ebscohost.com/ehost/pdf?vid=3&hid=11&sid=a0ea9afae64f-4c42-9890-0dd1a83a2f35%40sessionmgr13.
7.
A.
Van Heuvelen
, “
Overview, case study physics
,”
Am. J. Phys.
59
,
898
907
(Oct.
1991
).
8.
L. C. McDermott, P. S. Shaffer, and the University of Washington Physics Education Group, Tutorials in Introductory Physics (Prentice Hall, Upper Saddle River, NJ, 2002).
9.
S.
Bonham
, “
Graphical response exercises for teaching physics
,”
Phys. Teach.
45
,
482
486
(Nov.
2007
).
10.
R. J.
Roselli
,
L.
Howard
, and
S.
Brophy
, “
A computer-based free body diagram assistant
,”
Comput. Appl. Engin. Ed.
14
,
281
290
(
2006
).
11.
B.
Lane
, “
Why can't physicists draw FBD's?
Phys. Teach.
31
,
216
217
(April
1993
).
12.
W.
Sperry
, “
Placing the forces on free-body diagrams
,”
Phys. Teach.
32
,
353
(Sept.
1994
).
13.
M.
Mattson
, “
Getting students to provide direction when drawing free-body diagrams
,”
Phys. Teach.
42
,
398
399
(Oct.
2004
).
14.
A.
Puri
, “
The art of free-body diagrams
,”
Phys. Ed.
31
,
155
157
(
1996
).
15.
E.
van den Berg
and
C.
van Huis
, “
Drawing forces
,”
Phys. Teach.
36
,
222
223
(April
1998
).
16.
A. Arons, Teaching Introductory Physics, 3rd ed. (Wiley, New York, 1997).
17.
D. P.
Maloney
, “
Forces as interactions
,”
Phys. Teach.
28
,
386
390
(Sept.
1990
).
18.
This is is sometimes referred to as “object/agent” notation. An alternative is “agent/object” notation: Fg by the Earth on the person” or “Fg Earth/Person.” To my knowledge, a consensus notation has not yet emerged.
19.
T. L. O'Kuma, D. P. Maloney, and C. J. Hieggelke, Ranking Tasks Exercises in Physics (Prentice Hall, Upper Saddle River, NJ, 1999).
20.
From Ref. 8, HW-31.
21.
From Ref. 8, 30.
22.
Based on Ref. 8, 31–32.
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