Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Physics Coefficient of Static Friction Help?
Hello,
I am studying for my final, but I came across a question that I don't understand.
A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is .3. A horizontal force of 140N is applied to the box. What is the friction force on the box?
a.) 0.0N
b.) 1.65N
c.) 42N
d.) 140N
e.) 160N
I thought that the answer was 160N, because .3 * (55 * 9.8) = 160N. However, the answer key states that it is 140N. Could someone explain this to me?
1 Answer
- pierrot bulesLv 77 years agoFavorite Answer
http://hyperphysics.phy-astr.gsu.edu/hbase/imgmec/...
Normal force N = m * g = 55 * 9.8 = 539 N
Friction Ff = µ N = 0.3 * 539 = 161.7 N
Your answer is good
Application of Newton's second law to a single mass.
If an applied force F=140N is opposed by friction with friction coefficient mu =0.3 acting on mass m=55 kg then the the frictional resistance force is 161.7N and the net force is =-21.7 N.
http://hyperphysics.phy-astr.gsu.edu/hbase/acmas2....
Goodbye
