Crate Friction on Horizontal Floor


by VinnyCee
Tags: crate, floor, friction, horizontal
VinnyCee
VinnyCee is offline
#1
Oct17-04, 06:53 PM
P: 492
I have a problem with an answer that I don't know how to arrive at.

There is a 35 kg crate on a horizontal floor that a person is pushing with a 110 N force. The coefficient of static friction is 0.37. What is the maximum value f of s, max for which the crate will not move?

I thought that the answer is f of s, max = (coefficient of static frction)(35 kg)(9.8 m / s^2) = 127 N. However, the book lists an answer of 130 N. Am I going about his problem correctly?
Phys.Org News Partner Science news on Phys.org
NASA's space station Robonaut finally getting legs
Free the seed: OSSI nurtures growing plants without patent barriers
Going nuts? Turkey looks to pistachios to heat new eco-city
BLaH!
BLaH! is offline
#2
Oct17-04, 07:17 PM
P: 38
You're absolutely correct! [tex]f_{s, max} = \mu_s N = \mu_s mg[/tex] Because there are only 2 significant digits in the values for [tex]m, \mu_s[/tex] etc., the answer should be expressed with only 2 significant digits. You got an answer of 127 N which contains 3 significant digits. The book simply rounded up to 130 N to express the answer in 2 significant digits. Wasn't that simple? You were doing everything correctly!
VinnyCee
VinnyCee is offline
#3
Oct17-04, 08:37 PM
P: 492
Thank you for the reassurance! I don't think I would have gotten any further in the assignment stressing over that one little answer!


Register to reply

Related Discussions
friction and horizontal movement Introductory Physics Homework 11
Friction and Horizontal Force Introductory Physics Homework 2
Pulley Problem, 1 crate hanging, 1 crate on an incline Introductory Physics Homework 1
friction and a crate Introductory Physics Homework 7
Horizontal force with a crate at a 27 degree angle Introductory Physics Homework 4