PASCO ME-6855 Tension Protractor - Manual (Page 10)

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T e n s i o n P r o t r a c t o r E x p e r i m e n t 2 : B o o m i n S t a t i c E q u i l i b r i u m
8
Requirement #1 also implies that the sum of the force components in the x- and
y-directions must each separately be zero:
(eq. 2-3)
(eq. 2-4)
Another way of stating Requirement #2 is that the sum of all the clockwise torques equals
the sum of all the counterclockwise torques:
(eq. 2-5)
Procedure
1. Measure the masses of the meter stick and a hooked mass (use the mass marked
500 g). Record these masses in Table 2.1.
2. Balance the meter stick on a sharp edge, such as the edge of a table, to find the center
of mass of the meter stick. Record the position of the center of mass in Table 2.1. This
is the point at which it is assumed that the total weight of the meter stick acts.
3. Clamp one of the long rods (90 cm long) vertically to the table (see Figure 2.1).
Attach a right-angle clamp to the rod near the table. Clamp the short rod to the verti-
cal rod to act as a pivot.
4. Slide the hole at one end of the meter stick over the short rod. The meter stick should
pivot freely on the rod.
Figure 2.1: Set-up
5. Tie a loop of string loosely around the meter stick. This will be used to hang the
hooked mass.
F
ix i
∑
0 =
F
iy i
∑
0 =
τ
clockwise
∑
τ
counterclockwise
∑
=
hooked mass
Tension Protractor
short rod acting
as pivot point
string
meter stick
right-angle clamp