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: Exerted force?

  1. Dec 14, 2009 #1
    A 950 kg car starts from rest and reaches a velocity of 50.0 km/h in 8.50 s. If the driver has a mass of 75.0 kg, what force is exerted on the car and driver during this time interval?

    I am very confused on this question. I was thinking:

    950kg+750.kg=1025
    50.0/3.6 =13.88 +8.5 = 22.38s

    1025/22.38 .... but obviously all of that is wrong seeing as how it doesn't give me any of answers I can choose from :( help! what am i doing wrong
     
  2. jcsd
  3. Dec 14, 2009 #2

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    the mass of the car and driver is 1025 kg, OK
    please watch your units, 13.88 m/s is the velocity of the car after 8.5 seconds, then its acceleration is v/t, not v + t, and
    Where does this this formula come from? Please write out your relevant equations.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook