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

Centripetal force

Extracts from this document...


Student Name: WONG Wing Yan

Class and class no. : 6G2 (22)

Date of experiment: 11th March, 2009

Experiment 2 - Centripetal force


In this experiment, we are going the centripetal force for whirling a mass around a horizontal circle; then we compare experimental result with the theoretical value given by the formulaimage00.pngimage00.png.


  • Rubber bung
  • 1.5m of nylon string
  • Glass tube about 15cm long( wrapped by rubber tubing)
  • Labels
  • 50g slotted weight
  • Meter rule
  • Wire hook
  • Stop-watch




When a mass m attached to a string id whirled around a horizontal circle with radius r, according to the Newton’s First Law of Motion, there must be a force acting on it. It is a centripetal force for maintaining the circular motion. To produce centripetal acceleration, a centripetal force is needed. The centripetal force is given by


where image17.pngimage17.png is the angular velocity of the circular motion. The force is provided by the tension of the string and it must be directed towards the centre of the circular path.

We can substitute image34.png into the formula for F,

...read more.


Time for 50 revolutions 50 t/s





Data analysis and Results

Tabulate the results as follows:

Mass of rubber bung m = 0.01369g

Mass of slotted weight M: 0.05kg

Tension in string T = Mg = 0.05x9.8N = 0.49N

Length of string image05.pngimage05.png /m





Time for 50 revolutions 50 t/s





image08.pngimage08.png/rad image09.pngimage09.png










Mean image12.pngimage12.png = (0.4309+0.5281+0.5520+0.4885) =0.4999 N

Standard deviation image13.pngimage13.png = 0.0458


The percentage error between the theoretical value of the tension 𝑇 and the experimental value image12.pngimage12.pngis


The experimental value image12.pngimage12.pngis larger than theoretical value tension 𝑇, since there is some source of error in this experiment.

        Firstly, the position of the paper clip may not be the same, since the label indicate the length of the string, L fluctuates during the experiment, the length of the string beyond the upper opening is not constant. From the formula :


when the value of L is increased, the experimental result will be larger than the theoretical result. Oppositely, when the value of image05.png is decreased, the experimental result will be smaller than the theoretical result. Therefore, the results are affected by different value of image05.pngimage05.png.

...read more.






For the horizontal circular motion:




From the equation,



We can know that when the angular velocity image32.pngimage32.pngincreases, image33.pngimage33.pngwill also increase.


        In this experiment, we try to measure the centripetal force by whirling a mass in a horizontal circle for circular motion. We show that image28.pngimage28.png regardless of the angleimage04.pngimage04.png.

We compare the experimental value to theoretical value and find that the experimental one is a bit larger than the theoretical value, which is due to the error of this experiment.

It is also clear to show that image04.pngimage04.png is a constant. And from the formula, image35.pngimage35.pngrimage36.pngimage36.png, we can know the relationship between m and r, which is image37.pngimage37.png.

We can improve the experiment by moving the rubber bung in a constant speed. Also, the rubber bung should be set in a horizontal circular path. We should also keep the length of the string beyond the upper opening constant. The time for more revolutions of the circular motion could be taken for a more precise result.


  • New Way Physics for Advance Level – Book1(Mechanics) ; Manhattan Press (H.K.) LTD, page 172-173
  • http://en.wikipedia.org/wiki/Centripetal_force

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Mechanics & Radioactivity 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

See related essaysSee related essays

Related AS and A Level Mechanics & Radioactivity essays

  1. Centripetal motion. The objective of this experiment is to verify whether the tension ...

    The rubber bung was kept about 80cm (l) from the upper end of the glass tube. 4. The glass tube was held in a vertical position. The rubber bung was swirled over the head of the one who swirl it in a horizontal plane. 5. The angular speed of the rubber bung was increased until the paper marker

  2. Objective To measure the centripetal force for whirling a mass round a horizontal ...

    Procedure 1. Construct the centripetal force apparatus as shown in the following figure. 2. Find the mass of the rubber bung and the screw nuts. The weight of the screw nuts gives the tension T in the string. 3. Measure a length of the nylon string from the rubber bung to the glass tube.

  1. Use of technology in a hospital radiology department. The department of imaging is one ...

    ==> in UCLH there is policy and procedures provide for carer to follow when dealing with chemical and hazardous substance, they have provide separate room in each department to store all cleaning materials and disinfectants and they wear gloves when dealing with chemical.

  2. Multi-bladed Pumps. Does the number of propellor blades affect the efficiency of a ...

    The major difficulty with this experiment is the unpredictable nature of the propellers - unlike many other things physics, it is not easy to find a good estimate of what will happen in textbooks or online. One way of ensuring good results is to measure the variables to a reasonable number of significant figures.

  1. Young's Modulus of Nylon

    By calculating engineering stress, the effect of this variable can be negated. Safety Whilst the practical side of this investigation does not include any particularly dangerous apparatus or methods, there are still some safety considerations to be taken. Eye protection will have to be worn whilst the nylon has stress

  2. EvaluationThis article of "What We Know About Police Use of Force" is helping in ...

    * Garner and collegeues report that the race of a suspect and officer is not predictive of use of force, however incidents involving male police officers and male suspects are more likely to involve force. - They found that alcohol impairment by suspects was a consistent predictor of police use

  1. Drayton Manor Theme Park: Centrepedial Force

    "centre-seeking" force, as it is always directed towards the centre of the circular motion.2 Without this centripetal force the passengers of Cyclone would fly off at a tangent to the curve. The reason I feel almost glued to the floor of the carriage and do not fall about the carriage is because of my inertia.

  2. See how the angle of a ramp affects the speed of a cylinder moving ...

    = Distance (m) / Time (s), we can ascertain the speed of the cylinder on its way down the ramp.

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