Purpose: The purpose of this activity is to help students learn how to measure force and sketch force arrows.

Hypothesis:  When the individual forces on an object are measured, then the total forces can be combined to determine the resultant net force.

Materials: spring scale, ruler, book, string, objects

Procedure:

Have students pull each object at a slow, constant speed across a flat surface using the spring scale.  They may need to attach the scale to the object using string.  Students should record the force required to pull each object.  Next, have the draw force arrows for each object.  The arrows should be drawn to scale using a scale factor of 1 cm per each newton of force.