Understanding Vectors - Vector Addition
By participating in a group activity, students will learn how to add force vectors. They will see the significance of direction when adding vector quantities.
- Differentiate between scalar and vector quantities.
- Graphically add vectors.
- Identify examples of vectors and scalars.
Context for Use
Resource Type: Activities:Classroom Activity:Short Activity:Demonstration, Activities:Classroom Activity
Grade Level: High School (9-12)
Description and Teaching Materials
The actual activity begins by hanging a two kilogram mass from a spring scale which is calibrated in Newtons. The reading will be approximately 20 N. Then the same mass is suspended from a string (approximately 2 meters long) which is hanging from two spring scales which are attached to the blackboard. The mass is not placed in the middle, but closer to one end than the other. The readings of both spring scales are recorded, and the direction of force of each spring scale is marked by tracing the string on each side of the mass. An appropriate scale is chosen, and vectors are drawn to represent the force of each spring scale. When the force vectors are added to each other, the resultant should be very close to 20 N straight up (to balance the weight of approximately 20 N down). It becomes clear that adding the magnitudes of the two forces as scalars gives an incorrect total force, but adding them as vectors gives an appropriate resultant force.
-2 spring scales calibrated in Newtons
-One 2 m piece of string
-One 2 kg mass
Teaching Notes and Tips
Spend adequate time dealing with how to measure angles when adding the vectors.
II.E.1,2 Forces of Nature