Lab Workbook

advertisement
Physics 3204 –Core Labs
Core Lab #1 – Initial Velocity of a Projectile
Purpose:
To find the initial velocity of a projectile.
Equipment:
Steel Ball, retort stand, test tube clamp, grooved ramp, carbon paper, blank paper, metre stick,
plumb line, tape
Procedure:
1. Create an inclined plane similar to the one on page 119 in your text.
2. Position the ramp a few centimeters behind the edge of the table.
3. Practice rolling the steel ball down the ramp a few times and adjust the height of the ramp
so that the ball does not bounce when it hits the table. Note where the ball is landing on
the floor at this point.
4. Place a piece of paper on the floor and tape it there so that the center of the paper is
approximately where the ball hit the floor.
5. Using the plumb line mark the floor with a piece of tape directly below the edge of the
table.
6. Place a piece of carbon paper on the sheet of plain paper.
7. Roll the ball down the ramp so that it lands on the carbon paper.
8. Remove the carbon paper and measure the distance from the edge of the table to the mark
made by the ball landing on the paper. (You marked the edge of the table on the floor
using a plumb line in step 5.)
9. Record your measurement in Table 1_1.
10. Repeat 9 more times.
11. Measure and record the height of the table in the space provided.
Analysis: (Refer to page 785-6 of text for parts 2 – 4)
1. Calculate the average (mean) horizontal distance traveled by the ball and record it in the
space provided next to table 1.
2. Estimate your instrumental uncertainty and explain how you arrived at that estimation.
(see Appendix B on pages 784 –786 ) [ 3 Marks]
___________________________________________________________________________
___________________________________________________________________________
____________________________________________________________.
3. Estimate your procedural uncertainty and explain how you arrived at that value. (see
Appendix B on pages 784 –786 )
[ 3 Marks]
___________________________________________________________________________
___________________________________________________________________________
_______________________________________________________.
4. Calculate the standard deviation for the horizontal distance and record it here.
(see Appendix B on pages 784 –786 )
 = ______ [ 2 Marks]
Physics 3204 –Core Labs
Data:
Table 1-1
Trial #
[ 5 Marks]
Distance
(m)
Trial #
1
6
2
7
3
8
4
9
5
10
Analysis: (Page 119)
Calculation #1:
[ 3 Marks]
Calculation #2: [ 3 Marks]
Discussion #2
[ 2 Marks]
Discussion#4
[ 2 Marks]
Discussion #5
[ 2 Marks]
Discussion #6
[ 2 Marks]
Distance
(m)
Height of the table =
________m
[1
Mark]
Physics 3204 –Core Labs
Core Lab #2 – Centripetal Force and Centripetal Acceleration
Purpose:
To determine the relationship between centripetal force (centripetal acceleration)
and radius, period and frequency.
Hypothesis: Describe how you expect the centripetal force of an object spinning in a
horizontal circle will relate to: [ / 3]
Frequency:_____________________________________________________________________
Period:________________________________________________________________________
Radius:_______________________________________________________________________
Equipment:
Centripetal force apparatus, standard mass set, meter stick, stopwatch, safety goggles
Important Notice:
Safety goggles are not optional in this lab; all students must wear safety
goggles until told to remove them.
Part A – Changing mass (constant r)
Procedure:
1. Working with your group using the apparatus supplied, place a total of 200 g at the end of the
string.
2. Holding the 200 g mass in your hand, swing the rubber stopper in a horizontal circle above
your head so that the last dot on the string is just below the pen.
3. Increase the speed of rotation until you can remove the hand holding the mass and maintain
the position of the dot at the bottom of the pen. This gives the string a radius of 1.0 m. Some
practice may be necessary to maintain the dot's position.
4. Once you have mastered the technique above have another member of your group use a
stopwatch to time 10 rotations of the rubber stopper.
5. Record the time for 10 rotations in table 2-1 provided.
6. Repeat steps 4 and 5 as you increase the mass in increments of 100.0 g up to a total mass of
700.0 g
Analysis:
1. Calculate the gravitational force of each mass and place them in column 2 of table 2-1
provided. [The gravitational force (Fg = mg ) = centripetal force (Fc)]
Physics 3204 –Core Labs
2. Calculate period for all six data sets and place them in the table.
3. Calculate the frequency for all six data sets and place them in the table.
4. Plot a graph of centripetal force vs. period (Remember: period goes on the horizontal axis).
5. Describe the general relationship between centripetal force and period.
6. Plot a graph of centripetal force vs. frequency.
7. Describe the general relationship between centripetal force and frequency.
Part B: Changing r (constant mass)
Procedure:
1. Use your time from the first row in table 2-1 as your time in the last row of table 2-2.
2. With a mass of 200 g suspended from the string take the time for ten rotations for radius
0.80 m, 0.60 m, 0.40 m. These are marked as dots on the string. Record these values in
Table 2-2 provided.
Analysis:
1. Calculate and record period, frequency and frequency squared for each different radius in
Table 2-2.
2. Plot a graph of centripetal force vs. frequency squared. Do not connect the points; instead
draw four lines from the origin to each dot (see page 229 in text).
3. Draw a dotted vertical line close to the first dot, between that dot and the origin(see page
229 in text). This gives you four points of intersection between the vertical line and the
four plotted lines.
4. By interpolating each point of intersection across to the vertical axis you can get the
centripetal force acting for each radius. Record these values in table 2-3.
5. Plot a graph of centripetal force vs. radius for a constant f2.
6. Determine the general relationship between centripetal force and radius.
Complete discussion and conclusion on page 230 of text and submit with your lab.
Physics 3204 –Core Labs
Lab Data:
Table 2-1 [
/5]
Centripetal Force
[Weight] (N)
Mass ( Kg)
Time for 10
rotations(s)
Period (s)
Frequency (Hz)
0.200
0.300
0.400
0.500
0.600
0.700
Table 2-2
[
/5 ]
Radius
(m)
Centripetal Force
[Weight] (N)
0.40
1.96
0.60
1.96
0.80
1.96
1.00
1.96
Table 2-3
Radius
(m)
0.40
0.60
0.80
1.00
[
Time for 10
Rotations (s)
/2 ]
Centripetal Force
from interpolation of
graph (N)
Period (s)
Frequency
(Hz)
Frequency
Squared (Hz2)
Physics 3204 –Core Labs
Graph of Centripetal Force vs. Period
[
Proportionality Statement: [
/ 2]
(Describe the general relationship between centripetal force and period)
/ 5]
Physics 3204 –Core Labs
Graph of Centripetal Force vs. Frequency
[
/ 5]
Proportionality Statement: [
/ 2]
(Describe the general relationship between centripetal force and frequency)
Physics 3204 –Core Labs
Graph of Centripetal Force vs. Frequency Squared [
/ 5]
Physics 3204 –Core Labs
Graph of Centripetal Force vs. Radius
(for a Constant Frequency Squared)
[
Proportionality Statement: [
/ 2]
(Describe the general relationship between centripetal force and radius)
/ 5]
Physics 3204 –Core Labs
Discussion:
1. How do your proportionality statements relate to your hypothesis?
[
/ 6]
2. From your results, what centripetal force would be required to rotate the stopper
in a horizontal circle of radius 1.5 m with a frequency of 8.0 Hz?
Conclusion:
Are the theoretical equations for centripetal force true within experimental error? Explain
[
/ 3]
Physics 3204 –Core Labs
3. Core Lab #3 – Equilibrium in Forces
Purpose:
To Examine the First Condition for Static Equilibrium: the balance of forces.
Hypothesis: __________________________________________________________________
______________________________________________________________________________
Equipment: Force Table, protractors, graph paper, 3 pulleys, masses, builders level, string or
fishing line.
Procedure:
1. Set up the apparatus as shown setting 3 so that
it is 90°
2. Put two strings together across one pulley to
change the 4 pulley table into three pulleys.
3. Fasten 3 different masses m1, m2 and m3 on
each end.
4. Adjust the masses and the angles 1 and 2
until static equilibrium is reached. Measure the
angles 1 and 2 shown in the diagram and
record them in Table 3-1.
5. Record the masses of m1, m2, and m3 in Table 3-1.
6. Change masses m1 and m2 and then reset the apparatus to static equilibrium.
7. Record all masses and angles in Table 3-1.
8. Change 3 so that it is less than 90°
9. Change the angles 1 and 2 and the masses to reset the apparatus to static equilibrium.
10. Record all masses and the angles in Table 3-1.
Analysis:
11. Calculate the horizontal components of the cables connected to m1 and m2 using Fg cos
and put them in the Table 3-1.
12. Calculate the vertical components of the cables connected to m1 and m2 using Fg sin
and put them in the Table 3-1.
13. Calculate the force of gravity on the third pulley for rows 1 and 2 in Table 3-1 and place
the answers in the appropriate place in the table.
14. Calculate the components of force for the third pulley for row 3 in Table 3-1 and place
the answers in the appropriate place in the table.
Physics 3204 –Core Labs
Data:
Table 3-1
Masses (Kg)
m1
m2
m3
Angle
1
2
Forces by Masses
1 and 2 (N)
3
F1H
F1V
F2H
F2V
Forces by
masses 1
and 2 (N)
Forces by
Mass 3 (N)
FH
F3H
FV
F3V
Trial
1
Trial
2
Trial
3
Discussion:
1. How does the sum of the vertical components of masses 1 and 2 relate to weight of the
mass 3 in each trial of Table 3-1?
Trial 1:_______________________________________________________________________
______________________________________________________________________________
Trial 2:_______________________________________________________________________
_____________________________________________________________________________
Trial 3:_______________________________________________________________________
______________________________________________________________________________
2. Is the sum of all horizontal components in trials 1 and 2 approximately equal zero?
______________________________________________________________________________
3. How does the sum of the vertical and horizontal forces from masses 1 and 2 compare
with the vertical and horizontal forces of gravity for mass 3 in trial 3?
______________________________________________________________________________
4. Draw a free body diagram that illustrates the forces on the strings in trial 3.
Physics 3204 –Core Labs
Conclusion:
Error Analysis:
1. What is your main source of error in this experiment?
2. What are two other sources of error in this experiment?
3. How could this experiment be improved?
4. Reread the purpose of this Lab then write a concluding statement that relates to that
purpose.
Physics 3204 –Core Labs
4. Core Lab #4 – The Law of Electric Charges
Purpose:
To examine the attraction and repulsion of electrostatic charges.
Hypothesis: Predict the charges on the following materials when they are rubbed together
using the electrostatic series in Table 13.1 on page 530 of your text.
Test Material
Rubbed with
Polyethylene
Acetate
Ebonite
Glass
Wool
Silk
Fur
Silk
Positive
material
Negative
material
Equipment: A ring stand, string, 2 polyethylene strips, 2 acetate strips, 2 ebonite rods, 2 glass
rods, woolen cloth, cotton cloth, silk cloth, fur
Procedure:
1. Set up an electroscope as shown using
polyethylene as the suspended material.
2. Rub the polyethylene strip with wool to charge
the strip.
3. Obtain another polyethylene strip and rub it with
wool. Use this material (polyethylene) as the
“test material”.
4. Bring the test material(polyethylene) near the
one end of the suspended material and observe
what happens. The electroscope should swing
toward or away from the test material.
5. Record your observation in the data table
provided.
6. Rub the polyethylene test material with wool
again now use the wool as the test material. Record your observation in the table.
7. Repeat the experiment using all of the materials listed in the table.
Physics 3204 –Core Labs
Data:
Material
Electroscope
Rubbed with
Material
Test
Rubbed with
Observation
(Attraction or
Repulsion)
Polyethylene
Polyethylene
Polyethylene
Acetate
Acetate
Acetate
Ebonite
Ebonite
Ebonite
Glass
Glass
Glass
Wool
Wool
Wool
Cotton
Cotton
Cotton
Fur
Fur
Fur
Silk
Silk
Silk
Polyethylene
Wool
Acetate
Acetate
Cotton
Polyethylene
Ebonite
Fur
Glass
Glass
Silk
Ebonite
Charge on
test material
(Positive or
negative)
Wool
Polyethylene
Cotton
Cotton
Acetate
Wool
Fur
Ebonite
Silk
Silk
Glass
Fur
Discussion:
1.
What effects do like charges have on one another?
2.
What effects do unlike charges have on one another?
3. In the following tale list the materials that became positively charged and the material they were rubbed
with.
Positively charged
When rubbed with
material
4.
In the following tale list the materials that became positively charged and the material they were rubbed
with.
Negatively charged
When rubbed with
material
5.
List any materials which remained neutral.
____________________________________________________________________________________________
Physics 3204 –Core Labs
Error: List three things that may have affected your results:
1. ____________________________________________________________________
2. ____________________________________________________________________
3. ____________________________________________________________________
Conclusion:
Look at the electrostatic series below. How does your electrostatic series compare with this
one?
_____________________________________________________________________________
_____________________________________________________________________________
MORE POSITIVE
rabbit's fur
glass
mica
nylon
wool
cat's fur
silk
paper
cotton
wood
acrylic
cellophane tape
polystyrene
polyethylene
rubber balloon
saran wrap
MORE NEGATIVE
The electrostatic series is based on Benjamin Franklin declaring that amber became negative
when rubbed with fur. Describe the implications on this experiment if Franklin had set the
convention by declaring that glass becomes negative when rubbed with silk.
Physics 3204 –Core Labs
Core Lab #5: Electric Circuits (14.1 in text)
Purpose:
To quantitatively verify Kirchoff’s Current and Voltage Laws for series and
parallel Circuits.
Procedure:
Part A - Series Circuit:
1.
Obtain a Digital Multimeter and set the meter to 20 DC Volts (ask teacher for
assistance)
2.
Plug in your power supply and adjust the knob to about 1/4 power.
3.
Place the red lead of your multimeter on the red connection of the power supply and the
black lead of the multimeter to the black lead of the power supply. Adjust the power
supply knob until you get a reading of approximately 3.0 Volts.
4.
Unplug the power supply and connect the circuit as shown below.
5.
6.
7.
Disconnect the red wire from the power supply at “A”.
Set your multimeter to resistance in the 2000 ohm range. (Look for 2K)
Connect your meter to the circuit at points A and D. This gives you the total circuit
resistance. ( It should be between 1600 (1.6K) to 2000 (2K) ). Record the value table
14.1 supplied.
Note: All values recorded in the procedure go in the “measured” columns of the tables.
8.
Find and record (in table 14.1) the actual resistance of each resistor by connecting your
meter across each of the following:
a.
A-B (resistor 1)
b.
B-C (resistor 2)
c.
C-D (resistor 3)
Physics 3204 –Core Labs
9.
10.
11.
12.
Reconnect the entire circuit and set your multimeter back to the 20 DC Volts range.
Plug your power supply in.
Connect your meter across points A-D to get your total voltage and record it in table 14.1.
Find and record the voltage drop across each resistor by connecting the multimeter
across each of the following points:
a.
A-B (resistor 1)
b.
B-C (resistor 2)
c.
C-D (resistor 3)
VERY IMPORTANT NOTE: You must now reconfigure the multimeter to act as an ammeter. To do so
remove the red lead from the meter and connect it to the “2A” connection on the meter. Then set your
meter on the 2 mA DC range.
13.
14.
Disconnect the wires at point D and connect the multimeter to each of the disconnected
wires. This gives your total circuit current record it in table 14.1.
Reconnect the wires at point A. Find and record the current through each resistor by
disconnecting the circuit at each of the following points. (One point at a time):
a.
A
(resistor 1)
b.
B
(resistor 2)
c.
C
(resistor 3)
Note: You must now reconfigure the multimeter to act as an ohm/voltmeter again. To do so remove the
red lead from the “2A” connection and place it back where it was originally.
Physics 3204 –Core Labs
Part B- Parallel Circuit
15.
Rewire the protoboard as shown in the diagram below:
16.
Disconnect your power supply from the circuit and remeasure the voltage supplied from
the power supply using the same method as step 3 above. Record the value in table 14.2.
With the power supply still disconnected, set your meter to measure resistance in the
2000 ohm range. (Look for 2K) and measure across points A-D. This gives the total
resistance for the circuit record it in table 14.2. ( The value should be less than 200.)
Since the resistors we are using are the same as in the last part copy the values of the
resistors in table 14.1 to table 14.2.
Reconnect the power supply to the circuit.
Find and record the voltage drop across each resistor by connecting the multimeter
across each of the following points:
a.
A-D (resistor 1)
b.
B-E (resistor 2)
c.
C-F (resistor 3)
17.
18.
19.
ANOTHER VERY IMPORTANT NOTE: You must now reconfigure the multimeter to act as an ammeter to
measure current. To do so remove the red lead from the meter and connect it to the “2A” connection on the
meter. Then set your meter on the 20 mA DC range.
20.
21.
22.
23.
After reconfiguring your meter to measure current. Disconnect resistor 1 from the circuit
at point A. Place a wire in the hole that the resistor was in. Measure the current through
this point by connecting black lead of the meter to the wire and the red lead to the
resistor. Record your value in table 14.2.
Remove the wire and reconnect the resistor as it was originally in Part B.
Repeat step 20 for resistor 2 and resistor 3.
Complete Discussion questions 1 and 2 and the Conclusion sections of the lab on page
626.
Physics 3204 –Core Labs
Table 14.1
Circuit
Element
Resistance
Calculated
Resistor 1
(330 )
Resistor 2
(470 )
Resistor 3
(1000 )
Total Circuit
Value
Measured
Voltage
Calculated
Measured
Current
Calculated
Measured
Physics 3204 –Core Labs
Table 14.2
Circuit
Element
Resistance
Calculated
Resistor 1
(330 )
Resistor 2
(470 )
Resistor 3
(1000 )
Total Circuit
Value
Measured
Voltage
Calculated
Measured
Current
Calculated
Measured