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!

Help: Force & acceleration

  1. Sep 25, 2004 #1
    1) A mass 1.3 kilograms is pushed with a horizontal force 17.5 Newtons of a smooth inclined plane which bears an angle 12.5 to the horizontal. Find the acceleration of the mass (g = 9.81 m/s).

    I got 2.12, but it was wrong, and I don't know why.

    2) A mass 1.9 kilograms is pushed with a horizontal force 20 Newtons of a smooth inclined plane which bears an angle 27 to the horizontal. Find the distance the block moves in 6.5 seconds (g= 9.81 m/s2).

    I got 198.13, but it was wrong, and I don't know why.
     
  2. jcsd
  3. Sep 25, 2004 #2
    This is a matter (also for the second question) of using the right components of given forces. The given force is HORIZONTAL so you need the component of this force in the direction that the object moves: 12.5 degrees upwards.

    F = ma so that a=F/m and F = 17.5*cos(12.5)

    I get 13.1 m/s² for this one

    Then there is gravity F =m*g pointing down vertically. The component of this force along the inclination is -m*g*sin(12.5). And minus because it points DOWN the y-axis...so the acceleration here is -2.1 m/s²

    So I get : 13.1 - 2.1 = 11 m/s² as an anwser...

    marlon

    same thing for the second question : draw a sketch and call the inclination the x-axis...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Help: Force & acceleration
Loading...