lab1 physics free fall EXEL
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PHYS1310_Expt1-FreeFall_Fall2020.docxINTRODUCTION
In this lab you will perform a simulated experiment to understand the motion of falling objects. The motion of a falling objects played a significant role in the history of science. A body falling freely under only the gravitational force (neglecting air resistance) will be examined and acceleration due to gravity (g) will be determined.
THEORY
A body that is falling freely is acted upon only by the gravitational force exerted by the earth, and this force is directed towards the center of the earth. This gravitational force is constant and the acceleration due to gravity (g) will be constant for a freely falling body (neglecting the air resistance).
Acceleration is defined as rate of change of velocity with time. That is:
PHYS.1310 Technical Physics I Lab
FREE-FALL MOITON SIMULAION
(1)
where = acceleration of the body, = initial velocity, = final velocity, = time interval
From equation (1), a plot of v vs. t should be a straight line, and the slope of this line is equal to acceleration, a.
Using the definition of average velocity (rate of change of displacement with time; it is the mean of initial and final velocity), one can find the relationship between displacement, y and time, t (for constant acceleration):
(2)
From equation (2), a plot of y vs. t should be a parabola (for constant acceleration). Further, the instantaneous velocity of the body at any instant during the motion can be determined by drawing a tangent to the displacement vs. time graph, at the corresponding instant of time. The slope of this tangent gives the instantaneous velocity.
In this simulation lab, the motion of a falling object will be observed, by measuring its position at various times. From the analysis of the data and graphs, the acceleration due to gravity will be determined. Use Excel for tables and graphs.
SIMULATION
Use the link below to go to the simulation:
Constant Acceleration Simulation (Duffy, BU)
Part I - A ball dropped from rest near the surface of the Earth
Reset the vertical axis to position and select ‘Motion 1’.
Be sure to record all of the data that you take. Use a table to record your data - time and position.
· Create a data table-1 of time (s) and position (m)
· Use the ‘step’ button and determine the time and position for every 0.2 seconds for the total time interval of 2 seconds.
BRIEF TUTORIAL ON HOW TO USE EXCEL (see Introduction to Excel handout)
· Your lab instructor will instruct you on – how to input data, plot a graph, fit data with a trend line and how to find the slope of a straight line.
ANALYSIS
For Part I
1) Create a 2nd data table that includes the following entrees:
time, position, time interval (, distance between two consecutive positions ,
and average velocity.
2) Plot Graph I: velocity versus time
3) Fit the points of Graph I with a straight line and determine its slope.
4) What is the expected value and meaning of the slope of this graph?
5) Calculate the per cent difference between the slope of the fitted graph and its expected value.
6) Plot Graph II: position versus time
7) Fit the points of Graph II with a parabolic curve.
8) Find the slope of two points on the fit to Graph II and compare them to the corresponding values in the data table.
Part II Other similar motions
· Run each of the other four motions (but don’t record the details). Observe and describe the similarities and differences for these motions.
