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: BASIC Centripetal Force PROBLEM HELP!

  1. Nov 20, 2006 #1
    Calculate the centripetal force on a 2000-kg automobile roudning a curve of 175 m radius at a speed of 50 km/h.

    ok
    so this

    Fc=mv^2/r
    i did 2000(50)(1000)(3600) / 175

    but this was incorrect. the answer is 2.2x10^3 N

    the 1000x3600 was to convert the km/h to m/s and i think that's correct so what did i do wrong here.
     
  2. jcsd
  3. Nov 20, 2006 #2
    The conversion is [tex]\frac{1}{1000}\frac{\text{km}}{\text{m}}[/tex], not [tex]1000\frac{\text{km}}{\text{m}}[/tex]
     
  4. Nov 20, 2006 #3
    thx for pointing that out but.
    i should be getting around 2200.

    so i do

    2000[(50)(.001)(3600)]^2 / 175
    but i get 370285...
    whats wrong here now?
     
  5. Nov 20, 2006 #4
    wait still... isn't 50km = 50000m?
    so i should multiply 50x1000?
     
  6. Nov 20, 2006 #5
    iim keep getting 2057 if i use 0.01
     
  7. Nov 20, 2006 #6
    Sorry, the hour to second conversion should be changed, not the km to meters.
     
  8. Nov 20, 2006 #7
    ok so if i do multiply 1000 or do "2000(50)(1000)(3600) / 175"
    i dont get the answer 2.2x10^3 N
    can you please help
     
  9. Nov 20, 2006 #8
    The 3600 hr/sec should be 1/3600. And remember to square. This will give an answer of about 2204.6.:biggrin:
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook