Vectors Practicum II
Goal:
The purpose of this practicum is to gain experience in adding three (3) vector
quantities experimentally, graphically, and computationally.
 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.
Vectors Practicum II
 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 act as the
equilibriant and balance the forces exerted on the strings by the other three
masses. Record as the Experimental Equilibriant.
 Remember that the resultant must be the same size as the equilibriant, but in the
opposite direction. Record the Expermental Resultant.
Vectors Practicum II
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.
Vectors Practicum II
 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
Theoretical  Experimental
% Error 
 100
Theoretical