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pendulum prac (1 Viewer)
- Thread starter Danger
- Start date
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“perform an investigation and gather information to determine a value for acceleration due to gravity using pendulum motion or computer assisted technology and identify reason for possible variations from the value 9.8 ms-2”
Aim:
To find the acceleration due to gravity.
Formula: T = 2π√(l/g)
Diagram:
I cannot provide one.
Equipment:
Method:
1. Setup the equipment as shown
2. Measure the length of the string
3. Pull the weights to one side creating a small amplitude
Note somewhere that the formula is only valid for small amplitudes, that small the the curved path of the mass can be well approximated by a straight line.
4. Release the weights and record the period of each swing 10 times.
Explain why, you make errors in time measurement mainly when turning on the stopwatch and turning it off. If your total error is about 0.1 s, then your percentage error is much smaller, if you were measuring 10 s instead of just 1 s.
Take each measurement three times and average.
5. Repeat steps 2 to 5 with different lengths of strings.
6. Record the lengths of the strings and the period of each swing.
For your results, create a graph where the y-axis is the Period squared (s2) and the x-axis is the length of the string (m)
You must find the value of g from the gradient.
Place in the formula T2 = 4π2(l/g) [T = 2π√(l/g)] into the form y = mx + b, making g the subject which will allow you to calculate the value of the acceleration due to gravity.
Conclusion:
The value of g = 9.8 ms-2. This was pretty accurately achieved.
Accuracy:
This can be improved by using different lengths of strings in 10 cm increments.
Repeat measurements more than three times.
Reliability:
Other groups in your class had very similar results.
Validity:
This experiment is only valid when the amplitude of the motion is less than 10 degrees and when the formula given is correct.
Risk assessment:
A mass falling on your foot, injury when cutting, a retort stand falling over, somebody being poked with a ruler.
- MFHS 2007
Aim:
To find the acceleration due to gravity.
Formula: T = 2π√(l/g)
Diagram:
I cannot provide one.
Equipment:
- Small brass weights in 50-gram increments about 1 or 2 cm wide (as an alternative to a bob)
- Different lengths of string up to one metre.
- Retort stand, boss, and clamp.
- G-clamp.
- Stopwatch.
Method:
1. Setup the equipment as shown
2. Measure the length of the string
3. Pull the weights to one side creating a small amplitude
Note somewhere that the formula is only valid for small amplitudes, that small the the curved path of the mass can be well approximated by a straight line.
4. Release the weights and record the period of each swing 10 times.
Explain why, you make errors in time measurement mainly when turning on the stopwatch and turning it off. If your total error is about 0.1 s, then your percentage error is much smaller, if you were measuring 10 s instead of just 1 s.
Take each measurement three times and average.
5. Repeat steps 2 to 5 with different lengths of strings.
6. Record the lengths of the strings and the period of each swing.
For your results, create a graph where the y-axis is the Period squared (s2) and the x-axis is the length of the string (m)
You must find the value of g from the gradient.
Place in the formula T2 = 4π2(l/g) [T = 2π√(l/g)] into the form y = mx + b, making g the subject which will allow you to calculate the value of the acceleration due to gravity.
Conclusion:
The value of g = 9.8 ms-2. This was pretty accurately achieved.
Accuracy:
This can be improved by using different lengths of strings in 10 cm increments.
Repeat measurements more than three times.
Reliability:
Other groups in your class had very similar results.
Validity:
This experiment is only valid when the amplitude of the motion is less than 10 degrees and when the formula given is correct.
Risk assessment:
A mass falling on your foot, injury when cutting, a retort stand falling over, somebody being poked with a ruler.
- MFHS 2007
davidbarnes
Trainee Mȯderatȯr
Don't you have a textbook or something that would have this outlined in it?
From HSC Online - http://hsc.csu.edu.au/physics/core/space/9_2_1/921net.html#net2
"perform an investigation and gather information to determine a value for acceleration due to gravity using pendulum motion or computer assisted technology and identify reason for possible variations from the value 9.8 ms-2
* You may be performing an investigation that has been planned by your teacher. There are several suitable investigations that will achieve this purpose. One suitable investigation is described here.
A procedure for determining a value for acceleration due to gravity
A value for acceleration due to gravity can easily and accurately be measured by observing the motion of a pendulum.
1. Construct a pendulum at least one metre long, attached at its top to a support (such as a clamp connected to a retort stand) and with a small mass tied to its lower end to act as the pendulum bob.
2. Measure the length (l) of your pendulum, from its point of attachment to the centre of mass of its bob.
3. Pull the pendulum aside and release it so that it starts swinging. Using a stopwatch (or other device for measuring time), begin timing at an extreme of the pendulum’s motion and time ten full swings (one swing = back and forth) of the pendulum. Divide this time by ten to get a value for the average period (T) of the motion. Using this averaging technique tends to minimise random errors.
The period of a pendulum depends upon the length (l) and the value of acceleration due to gravity (g), as described in the following equation:
Equation for the period of a pendulum
Rearranging this equation gives an expression that can be used to calculate g.
Equation rearranged
4. Substitute your values for l and T into this equation to determine a value for g.
* As you gather information during your investigation, you may need to carry out repeat trials to confirm the reliability of your results. Also, you may want to use other, more accurate, timing devices or procedures to minimise the effect of random errors. "
From HSC Online - http://hsc.csu.edu.au/physics/core/space/9_2_1/921net.html#net2
"perform an investigation and gather information to determine a value for acceleration due to gravity using pendulum motion or computer assisted technology and identify reason for possible variations from the value 9.8 ms-2
* You may be performing an investigation that has been planned by your teacher. There are several suitable investigations that will achieve this purpose. One suitable investigation is described here.
A procedure for determining a value for acceleration due to gravity
A value for acceleration due to gravity can easily and accurately be measured by observing the motion of a pendulum.
1. Construct a pendulum at least one metre long, attached at its top to a support (such as a clamp connected to a retort stand) and with a small mass tied to its lower end to act as the pendulum bob.
2. Measure the length (l) of your pendulum, from its point of attachment to the centre of mass of its bob.
3. Pull the pendulum aside and release it so that it starts swinging. Using a stopwatch (or other device for measuring time), begin timing at an extreme of the pendulum’s motion and time ten full swings (one swing = back and forth) of the pendulum. Divide this time by ten to get a value for the average period (T) of the motion. Using this averaging technique tends to minimise random errors.
The period of a pendulum depends upon the length (l) and the value of acceleration due to gravity (g), as described in the following equation:
Equation for the period of a pendulum
Rearranging this equation gives an expression that can be used to calculate g.
Equation rearranged
4. Substitute your values for l and T into this equation to determine a value for g.
* As you gather information during your investigation, you may need to carry out repeat trials to confirm the reliability of your results. Also, you may want to use other, more accurate, timing devices or procedures to minimise the effect of random errors. "
DEscribe the pendulum experiment. the materialz used and the problemz face and how you accounted for 'em. Also describe how u applied the eqn to t=2pisquare root l/g
if this doesnt help check hsc online or the new multiple choice dot point physicz book.
if this doesnt help check hsc online or the new multiple choice dot point physicz book.
twilight1412
Member
the easiest experiment would be the pendulum experiment
since its the most commonly seen
even in exams they would rarely give a different example (if there are any)
i did that one at home actually >_>
since its the most commonly seen
even in exams they would rarely give a different example (if there are any)
i did that one at home actually >_>