1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Pendulum & Basketball Lab(Accelration due to gravity)

  1. Nov 1, 2009 #1
    1. The problem statement, all variables and given/known data
    Hey guys, i had to do a lab in class where i set up a lab using a steel ball and tied to a string and tied to a stand. I had to release the pendulum from a 10 degree angle and measure 20 cycles of the pendulum.
    For the second lab, i had to drop a basketball from 3 floors and measure the time using a timer tape till it hit the ground.
    Some discussion questions were given to my by the teacher.

    1. The restoring force that brings the pendulum back to its equilibrium position is a component of the bob's weight, specifically force(sinx), where x is the angle at which the pendulum is displaced from equilibrium.
    a. Explain conceptually why the period of a pendulum decreases when he length increases and decreases when the acceleration due to gravity increases.
    b. Offer an explanation for why the period of the pendulum does not depend upon its displacement from equilibrium.
    (Think about average force, average acceleration, average speed, and the length of the path traveled when answering the question).

    2. For first part of the lab, offer possible explanations(specific, relevant and likely) for why the experimental value for the acceleration due to gravity might differ from the expected value. Explain how and why the error might have affected your results.

    3. According to the best-fit line for the velocity-time graph, what is the initial velocity of the basketball? How does the initial velocity of the basketball affect its acceleration, time to fall and final velocity? Justify answers(Neglect air resistance)

    4. (We graphed the results for the ball)
    The acceleration of an object in free-fall is constant and is equal to 9.8m/s/s. Are the results shown on your velocity-time graph as expected.(Came out as 8.164 m/s/s for slope of velocity) Offer possible explanations for the error
    Some things to think about(i made these up) for number 4
    -What effect does air resistance have on the acceleration of a falling object?
    -Several groups had to do a second trial because the paper ripped while the ball was falling. What might this indicate about additional forces acting on the ball?
    -What effect would additional forces acting on the ball have on its net force and on the acceleration?

    2. Relevant equations

    T = 2pisquare root of (L/g)

    3. The attempt at a solution
    Should i post my calculations/results? It seems this can be done without them.

    I do not expect fully answered questions. If i can get some help on them (where to start etc.,) it would be greatly appreciated.

  2. jcsd
  3. Nov 1, 2009 #2
    i know i didnt provide much of a solution but someone can please help out a little?
  4. Nov 1, 2009 #3
    are you not responding because i dont have any answers? i will have them by tommorow
  5. Nov 2, 2009 #4
  6. Nov 2, 2009 #5
    someone please help a little bit, it is due tommorow
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook