• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2
3. 3
3
4. 4
4
5. 5
5
6. 6
6
7. 7
7

# To determine the acceleration of free fall (g) using a simple pendulum. To achieve this I must research background information provided in the specification.

Extracts from this document...

Introduction

Chris Horswell                                                                      1st December 2002

Determine the Gravitational Field Strength (g)

at the Earths Surface, Using a Pendulum.

Aim: -

To determine the acceleration of free fall (g) using a simple pendulum. To achieve this I must research background information provided in the specification.

In my specification I am provided with the Periodic Time equation: -

L = Length - Measured in metres (m)

g = Gravity - Measured in Metres per second (ms  )

T = Periodic Time - Measured in second (s)

Background information

“This was produced by Galileo in 1632. He was inspired by a swinging lamp, strung form the ceiling of the Cathedral in Pisa; using his pulse as a stopwatch, he calculated that the oscillations of the lamp remained constant even when the oscillations were dying away.”

It was acting like a Pendulum.

A pendulum consists of a mass hanging from a string and fixed at a pivot point. Once released from an initial angle, the pendulum will swing back and forth with Periodic Motion.

1. ‘a’ to ‘b’ to ‘c’ to ‘b’ to ‘a’ = 1 oscillation.
1. at points ‘a’ and ‘c’ = greatest potential energy.
1. at point ‘b’ = greatest kinetic energy.

This is a diagram showing the motions of the pendulum and forces acting on it. It shows where the bob passes once swinging and the Simple Harmonic Motion it follows. Also shown above is where the greatest potential and kinetic energy is. We shall refer back to this later in our preliminary work.

Middle

Using an Electronic timer.

This is the use of an electromagnet, a ball bearing and a trapdoor. The timer starts when the ball bearing is released from the electromagnet and then stops when it enters the trap door. Using the Displacement equation : -

S = Displacement

t = Time taken

U = Initial velocity

a = Acceleration

Substituting in common factors (Gravity, Height and initial velocity) : -

With this we can find out the gravity by adding the height of the ball bearing from the trap door, and the time taken.

Using a ticker-tape timer.

This method shows the acceleration of a mass with small dots. The dots increase distance apart as the mass falls.  After this we separate the dots into 5 dot intervals, which represents 0.1 of a second.

If we then line these 5 dot intervals in a row it displays as a bar chart then  by measuring the gradient : -

We can find the acceleration of the mass (Gravity)

Using a light gate.

This is set up so the object falls through the set of light gates. Setting the light gates at different lengths apart give more accurate reading. To use this method a computer is needed and the information can be converted into metres per second instantly but equations can be used

also: -

Putting this into the equation for Acceleration we can work out gravity: -

But

Conclusion

Constant and Varying Factors

Constant Factors: -

1. Pendulum/Bob
1. Number of oscillations
1. Fiducial marker

Varying Factors: -

1. Length of pendulum

I shall be measuring the time it takes for 10 oscillations to occur using a stopwatch (seconds)

Prediction.

I predict that I shall get the value of 9.81ms   . I predict this because from research and common knowledge Galileo produced this almost 300 years ago and has become a legend since. But I cannot expect my results to show exactly 9.81ms   ,this is because of human error with the fiducial point, and air resistance with the bob.

Safety

The usual safety precautions should be enforced, safety goggles, long hair should be tied back and stools and bags under the desk. Extra precaution should be taken when walking about the lab as there are swinging weights about.

ApparatusDiagram

1. Clamp and Stand
3. 2 pieces of slated wood
4. Pendulum / Bob
5. Stool
6. Stop watch
7. 2 metre sticks
8. Protractor
9. Card and felt pen

Method

1. Set up as Diagram
2. Draw vertical line on card to make your fiducial point.
3. Let pendulum hang vertically to elign the fiducial point.
4. Once prepared, hold protractor at the top of the string and measure the pendulum out to 10º
5. Let go of pendulum and start stopwatch when u see it pass the fiducial point. (you may want to let it swing back and forth a couple of times to regulate the oscillations)
6. Once the pendulum has oscillated 10 times, stop the stopwatch and record the time.
7. Repeat 2 more times and record results.
8. Change length to 1.80 metres and repeat
9. Repeat for the other lengths until you have collected all your data.
10. Plot on Graph and work out the gradient

This student written piece of work is one of many that can be found in our GCSE Forces and Motion section.

## Found what you're looking for?

• Start learning 29% faster today
• 150,000+ documents available
• Just £6.99 a month

Not the one? Search for your essay title...
• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month

# Related GCSE Forces and Motion essays

1. ## The Simple Pendulum Experiment

4 star(s)

me see the effects of changing the mass of the pendulum on the time of the pendulum's oscillation and proceed to analyse my results. Length Experiment results Length (cm) A (s) A-2R (s) T (s) 80 56.8 56.4 1.88 90 59.8 59.4 1.98 100 62.8 62.4 2.08 110 65.5 65.1

2. ## Determination of the acceleration due to gravity using a simple pendulum.

The percentage error in the result I obtained is very small but it must be noted that I only got this result by eliminating what I thought were anomalous results and in their place assuming that the line I continued by ignoring the two anomalous results was an assumption of what the correct results would have been.

1. ## Determining the acceleration due to gravity by using simple pendulum.

* The spinning Earth also affects the value of g. At the equator, the spin effect is greatest resulting in a lowering of the value of g. As you travel from the equator to the poles, the spin effect on g shrinks to zero.

2. ## Investigating the period of a simple pendulum and measuring acceleration due to gravity.

The percentage error worked out to be 0.612%. Since this is a very small value it shows that the results I got are quiet accurate to give a reliable value for acceleration due to gravity. EVALUATION: The experiment I have done is quiet accurate in that the percentage error is only 0.612%.

1. ## Factors affecting acceleration

150g 1.62 1.55 1.47 200g 1.50 1.69 1.84 250g 1.63 1.80 1.38 300g 1.61 1.68 1.32 350g 1.30 1.53 1.63 400g 1.63 1.45 1.16 450g 1.53 1.34 1.66 500g 1.33 1.56 1.48 Conclusion From these results I can deduce that the prediction that I made was correct, as there is

2. ## Period of Oscillation of a Simple Pendulum

I have drawn a scatter-graph to show these results. The scatter-graph shows the results of my experiment (in red) and the theoretical results (in green). The green dots at which the red dot cannot be seen, have the best results as this shows that the results are close to the theoretical answer.

1. ## Measuring Acceleration due to Gravity using a simple Pendulum.

0.17% 0.61% 1.39% 0.700 0.14% 0.57% 1.28% 0.800 0.13% 0.53% 1.19% 0.900 0.11% 0.51% 1.15% 1.000 0.10% 0.47% 1.04% Percentage error of g = (percentage error of length) + 2(percentage error of period) The maximum percentage error of g = 3.92 8.

2. ## Investigate the factors which determine the damping of a compound pendulum to find an ...

will give a good opportunity to take a good range of results and should be the easiest to implement. All other factors however will have to be kept constant. Practical Procedure I am going to record damping as the amount of time taken for the amplitude of the oscillations of

• Over 160,000 pieces
of student written work
• Annotated by
experienced teachers
• Ideas and feedback to