Results 1 to 4 of 4

Thread: Finding the period (T) of a pendulum on Mars

  1. #1
    Super Member
    Joined
    Nov 2012
    From
    Hawaii
    Posts
    744
    Thanks
    2

    Finding the period (T) of a pendulum on Mars

    Word Problem: The first astronauts to visit Mars are each allowed to take along some personal items to remind them of home. One astronaut takes along a grandfather clock, which, on earth, has a pendulum that takes 1 second per swing, each swing corresponding to one tick of the clock. When the clock is set up on Mars, will it run fast or slow?

    The answer shows you that the clock on Mars will have a slower period on Mars (T = 2.45 sec.) than on Earth (T = 1 sec.). There's a section called "My Work Version #1", where I tried to solve the problem. The formula is pretty basic. Plug in acceleration of gravity (9.8 m/s^2) and the length of the string (1 m). With that approach I got T = 3.26.

    On the section called "My Work Version #2", I pretty much set T earth and T mars and tried to solve for T mars. At the end the value that I got under the square root is 0.166/1, but the answer key that they had is 1/0.166.

    So the bottom line is, I have no idea how they got the value of 0.166 how they solved for the period, T, of Mars.


    Attached Thumbnails Attached Thumbnails Finding the period (T) of a pendulum on Mars-img_2310.jpeg  
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Jun 2014
    From
    NJ
    Posts
    287
    Thanks
    101

    Re: Finding the period (T) of a pendulum on Mars

    I don't understand the step "Set each equal to each other and solve for T_mars." If a=b and c=d that does not mean that ab =cd. I think what you were thinking of is that if a=b and c = d then ad = bc. Hence what you should have is:

    $T_{mars} 2 \pi \sqrt {L/g} = T_{earth} 2 \pi \sqrt { L/(0.166g)}$
    Last edited by ChipB; Jan 29th 2018 at 04:05 AM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Nov 2012
    From
    Hawaii
    Posts
    744
    Thanks
    2

    Re: Finding the period (T) of a pendulum on Mars

    Quote Originally Posted by ChipB View Post
    I don't understand the step "Set each equal to each other and solve for T_mars." If a=b and c=d that does not mean that ab =cd. I think what you were thinking of is that if a=b and c = d then ad = bc. Hence what you should have is:

    $T_{mars} 2 \pi \sqrt {L/g} = T_{earth} 2 \pi \sqrt { L/(0.166g)}$
    I don't understand where 0.166 came from? How did they come up with that number?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Senior Member
    Joined
    Jun 2014
    From
    NJ
    Posts
    287
    Thanks
    101

    Re: Finding the period (T) of a pendulum on Mars

    Not sure. If I had to guess, it’s a mistake. I bet whoever came up with the answer using g_mars = 0.166 times g_earth was confused and used the gravitational acceleration of the moon by mistake, instead of Mars. It turns out that g_moon really is 0.166 times g_earth.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Finding the period of a system of ODE's
    Posted in the Differential Equations Forum
    Replies: 0
    Last Post: Mar 16th 2011, 07:16 AM
  2. Finding the speed of an object on Mars
    Posted in the Calculus Forum
    Replies: 7
    Last Post: Nov 5th 2010, 10:52 AM
  3. [SOLVED] Time period of simple pendulum(with a catch!)?
    Posted in the Advanced Applied Math Forum
    Replies: 1
    Last Post: Jun 1st 2009, 11:42 PM
  4. Period of Pendulum
    Posted in the Pre-Calculus Forum
    Replies: 4
    Last Post: Oct 20th 2008, 07:00 AM
  5. Finding the period (n)
    Posted in the Algebra Forum
    Replies: 4
    Last Post: May 2nd 2007, 10:31 PM

Search Tags


/mathhelpforum @mathhelpforum