Year 10 Science
Practical Report

When a body is acted upon by a force it experiences acceleration. There are a number of factors that could affect the acceleration of the body.

2014
Lachie Patterson 5/7/2014

Problem:
How does the mass of an object effect the acceleration of the object?
Hypothesis:
If the mass of the trolley is increased, the acceleration rate of the trolley decreases.
Explanation:
This happens because of Newton’s second law, which is, a larger mass accelerates less than a smaller mass when acted on by the same force.
Variables:
Independent: Mass of the trolley. Dependent: The acceleration of the object. Controlled: The position of the ticker timer, mass that is pulling the h trolley, same trolley, voltage and bench surface.
Fair Test:
To conduct a fair test, make sure that you do not change the materials needed throughout the experiment. Keep the same method throughout and also make sure the ticker timer stays in the same place.
Materials:
* 1x Ticker timer * 1x Power pack * 1x One meter ruler * 1x Scissors * 12x 1m Ticker tape * 1x Pen * 2x Red and or black leads * 1x Roll of string * 1x Set of 50g masses on hook * 1x Trolley * 1x Roll of sticky tape * 1x Safety glasses * 1x Hair tie if needed * Flat bench/table
Method:
1. Collect and put on safety glasses. If required, put hair up with hair tie. 2. Collect all materials and place on the bench/table. 3. Place ticker timer and power pack at the end of the bench with power supply. Plug in the power pack. 4. Connect the ticker timer to the power pack by attaching the red and black leads to the two terminals on the ticker timer and the two AC terminals on the power pack. If the power pack gets turned on, it should work. Make sure the power pack is set to 12 volts. 5. Using the one meter ruler, measure and cut 12 pieces of ticker tape, all measuring 1 meter 6. Take all the 50g masses off the hook and tie the hook to the end of the string. Get the trolley and place it on the opposite end of the bench to the ticker timer but directly in line with it. Make sure the trolley is on the very edge. Place the hook on the floor and keep letting out string until it is at the trolley height. Make sure the string still has tension in it. Then tie the string around the front axle of the trolley. 7. Get one piece of ticker tape and sticky tape to the rear axle of the troller. With the other end feed it through the ticker timer and underneath the carbon paper until the rear of the trolley is touching the ticker time. The hook should now be pulled off the ground and hanging in mid-air. Don’t let go of the trolley. 8. Get your partner to turn on the power pack, which will activate the ticker timer. As soon as that is on let go of the trolley without applying any excess force. This will mark the ticker tape. With the pen write on the tape how much excess there was in the trolley, in this case 0grams and what trial it was, in this case trial 1. 9. Repeat steps 7 and 8 but add an extra 50gram mass each time until you want to stop. 10. Once trial one has been completed, again repeat steps 7- to 9 until you have you desired amount of trials.
Results
Acceleration (A) = Net Force (N) Mass (M)
Final Speed = Distance Time

IV Mass (grams) | Distance of last 5 intervals (seconds) | Average | Final Speed (seconds) | Average Acceleration (seconds) | | Trail 1 | Trial 2 | Trial 3 | | | | 0 grams | 9.5 | 10 | - | 9.75 | 97.5 cm/s | 97.5 cm/s/s | 50 grams | 8.8 | 8.7 | 12.5 | 10.0 | 100 cm/s | 100 cm/s/s | 100 grams | 7.0 | 3.5 | 6.0 | 5.5 | 55 cm/s | 55 cm/s/s | 150 grams | 4.8 | 7.2 | 7.6 | 6.53 | 65.3 cm/s | 65.3 cm/s/s |

Analysis
In the graph, there is no trend in the data. The line of best fit proves that by have marks a long way off both sides the line however the line is sloping downwards. This data is not reliable because of the trials which were all over the place and as stated before the graph with the line of best fit did not look like what it should have. The marks on the graph were scatted which meant it is not reliable.
Conclusion
In conclusion the results gathered from this prac did not support the hypothesis. Which was, “If the mass of the trolley is increased, the acceleration rate of the trolley decreases.” The trolleys acceleration did decrease when the weight was increased but it did not decrease in a trend. Explanation This happens because of Newton’s second law, which is, a larger mass accelerates less than a smaller mass when acted on by the same force. Evaluation In this practical the reliability of the method was not very reliable. The ticker timer was not clamped down to the bench for the experiment which meant it may have moved a little bit affecting the results. When the ticker tapes were measured with a ruler it would have been giving possibly a different reading depending on the angle the person was looking at it from and also the markings may not be accurate. When the string got pulled every time it might have loosened a little bit again affecting the results. The validity of the method was not very successful. It was not a fair test because as stated before with the ticker timer not mounted down for example. The hypothesis did not match the results fairly. The trolley also had a bent axle half way through the experiment which slowed down the wheels for part of it. With the results gathered from this practical, the validity of the hypothesis was not valid. For this practical the fairness can be improved by clamping down the ticker timer. Also using stronger trolleys which will not bend at the wheels. There could also be more changes of the independent variable. Students could also complete more trials for a more accurate result. In this practical some extensions may be changing the force, test the wheels on the trolley with different materials and also a new surface could be trailed.