Name
Name
Name
Name
Period
Vectors Practicum II
Goal:
The purpose of this practicum is to gain experience in adding three (3) vector
quantities experimentally and computationally.
Apparatus:
Force Table
Masses
Protractor
Ruler
Graph Paper
Procedure

For each case, hang the given masses at the stated angles. Be sure to include
the mass hanger m  5.0 g  0.0050 kg in the total mass.

All directions are measured using counter-clockwise from 0  notation.

Adjust the pulleys downward until the strings are close to but not touching the top
surface of the force table.

By trial and error, find the angle for the fourth super pulley clamp and the mass
that must be suspended over the pulley so that its weight will balance the forces
exerted on the strings by the other two masses. This fourth force is called the
equilibriant because it establishes equilibrium. Remember that the equilibriant
is the same size as the resultant, but in the opposite direction.
Experimental Method of Finding Equilibrium



The knot should be centered over the hole in the middle of the center post
when the system is in equilibrium.
The anchor string should be slack.
Pull the knot slightly to one side and let it go. Check to see that the knot
returns to the center. If not, adjust the mass and/or the angle of the super
pulley clamp until the knot always returns to the center when pulled
slightly to one side.

Compute the resultant both computationally and graphically (chose a scale).
Record the results and calculate the percent error for each compared to the
experimental value. Everyone should complete the worksheet, with one set for
the group to be turned in at the end of the hour. PSYW

% Error 
Theoretical  Experimental
 100
Theoretical
Vectors Practicum II

page 2
Do not forget to include the mass hanger m  5.0 g  0.0050 kg in the total mass
Trial 1
Mass
(kg)
Force
(N)
Direction
(degrees)
0.055
15
0.075
80.
0.105
160
Force
(N)

Experimental Equilibriant
Mass
Force
Direction
(kg)
(N)
(degrees)
Experimental Resultant
Force
Direction
(N)
(degrees)
Computational Resultant
% Error
Direction
(degrees)
Force
Direction
Sketch a vector diagram of the situation and then compute the resultant in the
space below using the component method. Record the results above and
calculate the % error between this result and the experimental result. PSYW
Vectors Practicum II
page 3
Trial 2
Mass
(kg)
Force
(N)
Direction
(degrees)
0.055
0
0.075
90.
0.105
300.
Experimental Equilibriant
Mass
Force
Direction
(kg)
(N)
(degrees)
Experimental Resultant
Force
Direction
(N)
(degrees)
Computational Resultant
% Error
Force
Direction
(N)
(degrees)
Force
Direction

Sketch a vector diagram of the situation and then compute the resultant in the
space below using the component method. Record the results above and
calculate the % error between this result and the experimental result. PSYW