• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month

# centripetal force lab (DCP, CE)

Extracts from this document...

Introduction

Centripetal Force

Aim: To investigate the relationship between the rotation period T and the hanging mass M when an object is moving at a constant speed in circular motion.

Variables:

 Independent variable Hanging mass Dependent variable Rotation period Control variables - Number of rotation period- Length of string- Mass of the rubber stopper- Friction/ air resistance

Apparatus:

Meter stick, electric balance, timer, strings, rubber stopper, mass, plastic tube

Method: Data Collection

length of the string L = 35.0 cm ± 0.1cm = 0.350 m ± 0.001 m
mass of the rubber stopper = 38 g ± 1g = 0.038 kg ± 0.001 kg

The uncertainty of the string’s length, mass of the rubber stopper and time is taken to the smallest division of the measuring device (meter stick to measure length of string, electric balance to measure mass of stopper, stopwatch to measure time taken to complete 10 rotation period).

Raw Data

 hanging mass/ g ± 1g time taken for 10 rotation/ s ± 0.01s Average time for 10 rotation/ s ± 0.01s Random uncertainty In t (±s) 1st trial 2nd 3rd 4th 5th 50 7.01 7.79 7.37 7.68 7.26 7.42 0.16 100 5.84 5.21 5.41 5.96 6.04 5.69 0.17 150 5.16 4.79 5.35 4.70 4.97 4.99 0.13 200 4.78 4.66 4.50 4.12 4.83 4.58 0.14 250 3.82 4.01 4.41 4.68 4.22 4.23 0.17 300 3.62 3.77 4.06 3.93 4.28 3.93 0.13 Mean 0.15

The random uncertainty of the average time taken for 10 rotations is calculated by  Eg. Random uncertainty for time taken for 10 rotation period when the hanging mass is 50.0 kg = (7.79-7.01)/5=0.16

Data processing

Mass

Middle

0.100

0.58

0.52

0.54

0.60

0.60

0.57

0.02

0.150

0.52

0.48

0.54

0.47

0.50

0.50

0.01

0.200

0.48

0.47

0.45

0.41

0.48

0.46

0.01

0.250

0.38

0.40

0.44

0.47

0.42

0.42

0.02

0.300

0.36

0.38

0.41

0.39

0.43

0.39

0.01

Mean

0.02 From the graph, the best fit is does not pass through the origin and it is more like a negative curve. This may suggest a positive linear relationship between  and the hanging mass M.

Time

In order to have a linear graph, I have to plot  against the hanging mass. The average time taken for 1 period of each mass have to be processed to  .

For example, the rotation period when mass is 0.050 kg, is 0.74s. Then Final Data

 Hanging Mass/kg ± 0.001 kg ± 0.

Conclusion

The timing process of the rotation period causes a major random uncertainty in this experiment. Since there isn’t a certain point indicating the start and end of a rotation, timing the rotation period involve estimation of the starting/ending point of the rotation and may cause uncertainty.

Reaction time when using the stopwatch also causes uncertainty. A person cannot start or stop the stopwatch exactly at the point where rotation starts. The reaction time can be kept constant by having the same person as the timer throughout the experiment. However, in most cases, the reaction time starting and stopping the stopwatch may not always be equal and cannot fully cancel each other out. The percentage uncertainty can be reduced by timing more rotation period to reduce the significance of the reaction time on the data.

This student written piece of work is one of many that can be found in our International Baccalaureate Physics 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 International Baccalaureate Physics essays

1. ## Period of a loaded Cantilever (D, DCP, CE)

2.81 2.72 2.67 0.1 150.0 3.01 3.13 3.06 3.12 3.16 3.10 0.08 200.0 3.41 3.57 3.55 3.83 3.66 3.60 0.2 250.0 4.25 4.22 4.12 4.18 4.25 4.20 0.07 Mean: 0.2 The uncertainty of the measurement is taken to half of the smallest division of the measuring instrument.

2. ## Investigate the factors affecting the period of a double string pendulum

type of trend line for both the frequency and period such as exponential and not polynomial. It is because the small total length of the metal bar that this limited the range of values that I could have recorded. I could have until 17 cm (total length of the bar)

1. ## Boyle's law report (DCP, CE)

To calculate the theoretical gradient, I can use the ideal gas law PV=nRT or . Since the volume of 1 mole of ideal gas is 24.8L, the number of moles of gas in 25ml is mol. The universal gas constant R is 8.31 JK-1mol-1 and the temperature T is assumed to be a room temperature 298K.

2. ## Suspension Bridges. this extended essay is an investigation to study the variation in tension ...

The force acting on the cables in a suspension bridge can be due to the air pressure and wind velocity. This real-life practical setup propelled me to undertake an investigation - To study the variation in tension in the left segment of a relatively inelastic and an elastic string tied

1. ## Centripetal Force

?t = �0.005 s 1 6.47 2 7.47 3 6.91 4 7.44 5 7.00 6 7.32 7 6.35 8 7.50 9 7.79 10 8.47 Table 3.3 Result of Time taken for 10 revolutions for mass 30 g Trial Time Taken t(s)

2. ## In this extended essay, I will be investigating projectile motion via studying the movement ...

100N/cm will allow a larger portion of elastic potential energy stored in the spring to be converted into the linear kinetic energy of the metal ball. Furthermore, lubricating the runway of the container can reduce the friction between the container and the metal ball.

1. ## Oscillating Mass

Length of spring in cm after spring is hung Time of ten oscillations, T (s)

2. ## Horizontal Circular Motion Lab

±0.25s for the timing uncertainty should be a fair assumption. Then, Calculations for Tension of String: Since v is unknown, we must calculate it, and then we can substitute its value in the centripetal force formula Calculations For Since the rubber stopper travelled 10 revolutions on average in every 3.49s, • Over 160,000 pieces
of student written work
• Annotated by
experienced teachers
• Ideas and feedback to 