Objective: The primary objective of this lab is to review and refresh your knowledge of vectors which you will use extensively in labs to come.
For this lab, we will be using the PHET Simulation “Vector Addition”. For this simulation written in HTML5, you do not need Java or Flash on your computer.
Ensure that, prior to attempting this lab, you review and concepts of vectors in PHYS 251 textbook (Serway & Jewett: Chapter 3).
It is highly recommended that you watch the brief introductory videos posted on your lab Bb site in the same folder which contained this document before attempting this virtual lab.
WARNING: In contrast to the conventional notation used in class/textbook where upper case letters such as etc. are used to denote vectors, this simulation uses lower case letters such as . You will have to work through this inconvenience.
Explore: Run all four variations of the simulation. Explore 1D, Explore 2D, Lab, and Equations. Be inquisitive, explore, and enjoy!
Part A. Explore 1D
Goal: In this part of the lab, you will review adding/subtracting vectors in 1D.
Notes: This button erases all vectors on the grid.
This button resets the simulation window.
_____Click on Explore 1D tab at the bottom of the screen to get to the simulation on 1D vectors.
_____Make sure that the x-axis (horizontal) is selected, the grid is on, and the Sum box is unchecked.
S.1._____ Grab vector from the “vector bin” and place it on the grid about 2 – 3 divisions above the x-axis. Place such that its tail end is at x=-10 major grid line.
_______ Grab vector from its head (tip) by left clicking on it and note that you can change its length by moving the head in both the positive and negative x-directions. As you do that, note how ax and ay, the x and y components of , respectively, change (or not). Also note how and θ, the polar components of , respectively, change (or not).
Q.1 ______ Explain the behavior of ax, ay, , and θ, you observed as you moved the head of and changed its length.
S.2._____ Set to be in the positive x-direction and its magnitude to be between 15 and 20 divisions.
_______ Now grab vector from the bin and add it to by placing the tail of at the head of . Set to be in the positive x-direction and about half the length of .
_______ Now it’s time to plot vector , the sum of and . Check the box Sum . Vector will appear in a dark blue shade along the x-axis. Drag and position bout ten divisions above and such that its tail lines up with that of . Your simulation should look somewhat like the figure below.
Fig. 2_____ Include a figure of your own simulation in your lab report.
Tabulate data from this simulation in a table like the one below.
Table 2A
Vector | Magnitude | x-Component | y-Component | UV Notation* |
Sum | ||||
*Write the vector in terms of unit vectors and . Eg. .
Q.2 Comment on the data in Table 2A. For example, what is the relationship between the three x-components, three magnitudes, and between magnitudes and components? Do these relationships make sense? Explain.
S.3 _____ Grab the head of and change its magnitude/direction by dragging the head back and forth between the two ends of the grid while observing the behavior of .
Q.3 ______Does the behavior of make sense to you? Explain.
S.4._____ Here you will add to the mix and add a bit of complexity to the previous simulation. First, shift up vertically by a few units while ensuring that its tail and the head of are on the same vertical grid line.
______ Grab the head of and set it to be in the negative x-direction with a magnitude of about 30 divisions.
_______ Now grab vector from the bin and place it a few divisions above such that the head of and tail of are on the same vertical grid line. Set to be in the positive x-direction and its magnitude to be between 5 and 10 divisions. Your simulation should look somewhat like the figure at right.
Fig. 4_____ Include a figure of your own simulation in your lab report.