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: How to find tangential and normal acceleration?

  1. Jan 31, 2017 #1
    1. The problem statement, all variables and given/known data
    The problem asks for the tangential and normal acceleration of the acceleration. We were given that:
    $$a_x=c*cos[d*t]$$ and $$a_y=c*sin[d*t]$$ where c and d are constants.

    2. Relevant equations
    The book gives us
    $$a_t=(r\ddot{\theta}+2\dot{r}\dot{\theta})$$, (1)
    $$a_n=(\ddot{r}-r\dot{\theta}^2$$ (2)
    $$a=\sqrt{(a_t)^2+(a_n)^2}$$ (3)
    but I found online that
    $$a_t=\frac{dv}{dt}|v|$$ (4).
    Finally, I know that $$a=\sqrt{(a_x)^2+(a_y)^2}$$ (5).

    3. The attempt at a solution
    My attempt was to use equation (4) as we don't have a theta to find $$a_{tx}$$ and $$a_{ty}$$. But wouldn't that just be the given accelerations as we would integrate the acceleration just to take the derivative again?
    After that I would just solve (3) for $$a_n$$ of x and y and then plug both it in the (5) to find the magnitude of both $$a_t$$ and $$a_n$$. But I'm confused on how to find the tangential with either (1) or (4)?
  2. jcsd
  3. Jan 31, 2017 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I don't understand your equation 3. A correct version of that would be useful.
    Remember that the tangential acceleration is, by definition, the component of the acceleration in the direction of the velocity.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted