1. Not finding help here? Sign up for a free 30min 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!

Problems about calculating acceleration,velocity

  1. Mar 17, 2013 #1
    1. The problem statement, all variables and given/known data

    A car, as shown in the figure, is going in a curvilinear road. The size of the car will be neglected.

    2. Relevant equations

    Its acceleration is a = 0.5*e^t m/s^2.

    3. The attempt at a solution

    If it goes 18 meters on its way, then calculate its velocity and acceleration.

    I have one more question. A particle is making linear action. Its velocity in the origin is 4 m/s. If particle is slowing down with acceleration a = -3/2*v^1/2 m/s^2, calculate the elapse time and its taking way until it stops(v=0).

    Hope I could explain my questions clearly. How can I calculate them? Please help me.
     

    Attached Files:

  2. jcsd
  3. Mar 17, 2013 #2

    Doc Al

    User Avatar

    Staff: Mentor

    I assume that is the tangential acceleration.

    Given acceleration, how do you find velocity and distance?
     
  4. Mar 17, 2013 #3
    Yes, that is the tangential acceleration.

    I don't know how can I find their values, bacause it is going on a curvilinear road and there is a p value (you can see in the figure) p=30m. I must use this value of p.
     
  5. Mar 17, 2013 #4

    Doc Al

    User Avatar

    Staff: Mentor

    You'll use the radius to find the centripetal component of the acceleration.

    But first things first. How can you find the velocity and distance, given the tangential acceleration? Hint: Calculus.
     
  6. Mar 17, 2013 #5
    I must use the integral. Distance velocity v=0.5e^t+c1 and distance x=0.5e^t+c1t+c2 (c1,c2 constant values). But then, it is going 18 meters on the road.
     
  7. Mar 17, 2013 #6

    Doc Al

    User Avatar

    Staff: Mentor

    Good. What are c1 and c2? (Those depend on the initial conditions.)
     
  8. Mar 17, 2013 #7
    But I don't know where the car was on the road firstly. If at t=0, it was in origin, then c1=-0,5 , c2=0. But, this question don't tell us it was in the origin at first.
     
  9. Mar 17, 2013 #8

    Doc Al

    User Avatar

    Staff: Mentor

    You have to know the initial velocity and position or be able to make reasonable assumptions. That it starts from rest and at x = 0 seems reasonable. How did you get c2 = 0?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Problems about calculating acceleration,velocity
Loading...