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Homework Help: Data analysis work

  1. Jan 2, 2006 #1
    hi chaps, im doing this work on "investigating how the distance travelled by a ball bearing rolling down a slope affects the time taken" (i know riveting!! lol)

    and what ive got so far is a table of results (distance it rolled and then how long it took)

    ive also got : angle of inclination of ramp = 5 degrees
    mass of ball bearing = 16.7g
    diameter of ball bearing = 15.3mm

    and now basically ive got to do a various amount of equations im guessing to tell me lots of stuff!!

    but im not really sure what im susposed to be doing, i need a push to get me rolling (excuse the pun!!) so can anyone please help me!!

    thanks a lot, alex!
  2. jcsd
  3. Jan 2, 2006 #2


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    The height of the ball bearing determines the initial gravitational potential energy, which is transformed into kinetic energy of the ball bearing when it is released.

    The ball bearing is pulled downward by gravity, but since it is constrained by the incline, it must accelerate down the incline.

    Can you find the equation of motion for a rolling sphere?
  4. Jan 3, 2006 #3


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    It seems to me that the purpose of the experiment is to get the equations from the experiment, not to use them as already given. I would suggest this: For each angle, make a graph showing distance on one axis, time on the other. The shape of the graph should give you some ideas. A straight line, for example would be very simple.

    If the graph doesn't look simple, try "log-log" paper. That is graph paper where the lines are ruled by log x and log y rather than just x and y. If you don't have that, just mark the points using log x and log y rather than x and y. The point of that is: if y= ax3, then log y= 3 (log x)+ log a- its graph is a straight line.
  5. Jan 4, 2006 #4

    sorry guys i'm just really confused, what i have so far is an excell sheet with how long it took for it to roll down a slope (from a static start) ive plotted a graph, but its not staright, i think ive gotta square the distnce or square root it to get it straight but i really just dont know, please guys help!!!!!!! i beleive the idea of the work is to end up with a formula or equation bot sure which word to use!!!
  6. Jan 4, 2006 #5
    guys to get the graph staright would it be better to do, distance sqaured rooted against time taken, or velocity sqaured??
  7. Jan 4, 2006 #6


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    The whole point is for you to figure that out FROM the data. From what you have said so far, it wouldn't make sense to graph anything against "velocity squared" since you don't know velocity- you only recorded distance and time. TRY various possibilities: graph distance against time, squareroot of distance against time (same as distance against time squared), etc.

    The whole point of this experiment is NOT to use a formula you have learned from somewhere else but to use the data you recorded to lead you to the formula.
  8. Jan 4, 2006 #7

    but would it be useful to include velocity as i can work it by doing the distance/time taken.

    but on another note, i did a graph Average time taken Vs Sqaure root of distance from whcih ball beraing was released, then put a power trendline in to give me a staright line then worked out the slope of the line (0.40909) but i'm kinda out of ideas of what to do now, what is that telling and me and how can i relate this all back to the intial title.

    i came up with t=m(sqrt(d)) but im not sure how or what it means or if it helps lol!!!!

    thanks for all your help by the way i do appreciate it.
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