Prelab 2: Vector Addition Part 1 15
Name:
1. What is the difference between a vector quantity and a scalar
quantity?
2. Give two examples of scalar quantities and their units.
3. Give two examples of vector quantities and their units.
4. Are mass and weight the same thing? Explain.
5. Refer to figure 2.2 in the experiment file. What is the
length of vector B in cm?
6. Refer to figure 2.2 in the experiment file. What is the
magnitude of vector B in Newtons?
7. Refer to figure 2.4 in the experiment file. What is the
measurement of angle B in degrees?
8. Use the head-to-tail method to estimate the resultant vector
when you add 5.0 N at 45◦ standard position with10.0 N at 180◦
standard position. (A sketch is fine, no need to use a ruler and
protractor for right now, althoughyou will definitely need to in
lab!) Use the axes on the next page. Refer to figure 2.3 from the
experiment file.
9. What third vector would place the system described in the
previous question in equilibrium?
Experiment 2: Vector Addition Part 1 17
PROCEDURE
Part 1: Adding 2 Vectors Graphically
1. Your TA will provide you with 2 forces, ~A and~B. Record them
in the table and use the scale1.00N = 2.00cm to calculate the
length of vectorsyou will draw. Use graphical addition to find
theresultant vector ~R=~A+~B. Show your work in thespace below.
Label each axis and vector clearly.
Vector Magnitude (N) Scaled to cm Direction, θ
~A
~B
Resultant
Part 2: Adding 3 Vectors Graphically
2. Your TA will provide you with a third force ~C.Record the
vectors in the table and use the scale1.00N = 2.00cm to calculate
the length of vectorsyou will draw. Use graphical addition to find
theresultant vector ~R=~A+~B+~C . Show your work inthe space below.
Label each axis and vector clearly.
Vector Magnitude (N) Scaled to cm Direction, θ
~A
~B
~C
Resultant
Part 3: Verify Result from Part 1
3. Use the level to make sure the surface of the forcetable is
horizontal.
4. Place force A on the force table. Adjust a pulleyclamp to be
at the right location and add the cor-rect amount of mass to a mass
hanger. How muchmass is that? Hint: the mass hanger also has
mass.Get as close as you can, given the masses availableto you.
5. (a) Is the system in equilibrium right now? (b)If not, what
could you do to place the system inequilibrium? (c) Where would you
need to place asecond pulley and how much mass would you
putthere?
6. Test your answer using the force table. What doyou observe?
Using that, describe how the equili-brant’s magnitude and direction
is related to vector~A’s magnitude and direction.
7. Design a procedure that will allow you to test youranswers
from Part 1. We want to know whether theanswer you found for the
resultant ~R is really equiv-alent to the combined forces ~A and
~B. How can youuse the force table to test your results? Hint:
thinkabout using an equilibrant vector. Describe yourprocedure:
8. Use the level to level the force table.
9. Take whatever measurements you need for the pro-cedure you
designed and record them in the datatable below. Label all rows and
columns. X outany rows or columns you don’t need.
10. Compare your graphical measurement of the re-sultant vector
(Procedure 1) with the force tablemeasurement of the resultant
vector (Procedure 3).Show your calculations for percent difference
in thespace below.
QUESTIONS
1. Show using the head-to-tail method that vector ad-dition is
commutative, that is, ~A+~B is equivalentto ~B+~A.
2. You are using the head-to-tail method for six vec-tors and
you find that the head of the sixth vectorends up at the origin,
which is also the location ofthe tail of the first vector. What is
the resultantvector equal to? Include a sketch of any six
vectorsthat fit this description.
3. Using an online tool, find the vector that pointsfrom Lewis
Hall to your home (choose your home-town address or your local
address). Give the re-sults in both polar notation and component
nota-tion.
