User's Manual

Vector Addition

Purpose

The purpose of this experiment is to use the force table to experimentally determine the force that balances two

other forces. This result is checked by adding the two forces using their horizontal and vertical vector components,

and by graphically adding the force vectors.

Theory

This experiment finds the resultant of adding two vectors by three methods: experimentally, by adding compo-

nents, and graphically

NOTE: In all cases, the force caused by the mass hanging over the pulley is found by multiplying the mass by the

acceleration due to gravity, 9.8 m/s

Experimental Method

Two forces are applied on the force table by handing masses over pulleys position at certain angles. Next, the

angle and amount of mass hanging over the third pulley are adjusted until the force from this pulley balances the

forces from the other two pulleys. The third force is called the equilibriant (F

) because it is the force that estab-

lishes equilibrium. The equilibriant is not the same as the resultant (F

). The resultant is the addition of the two

forces. The equilibriant has the same magnitude as the resultant, but it is in the opposite direction of the resultant

because it must balance the resultant. The equilibriant is the ‘negative’ of the resultant.

Setup

1. Assemble the force table as shown in the Assembly section. Use three super pulley clamps (two for the

forces that will be added and one for the force that balances the sum of the other two forces).

2. Arrange the strings from the String Tie over the pulleys.

Equipment Needed Equipment Needed

Super Pulley Force Table (ME-9447B) String (spool of thread)

Super Pulley Table Clamp (ME-9448B) Protractor

Mass and Hanger Set (ME-8979) Metric Ruler

Mass Balance (SE-8723) Sheet of paper (2)

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