Splung.com Physics Forum Forum Index Splung.com Physics Forum
Discuss physics or ask questions. Part of the Splung.com physics web site.
 
   SearchSearch   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Help Physics!

 
Post new topic   Reply to topic    Splung.com Physics Forum Forum Index -> Physics Help. Ask a Physics Expert
View previous topic :: View next topic  
Author Message
Delilah



Joined: 29 Mar 2010
Posts: 6
Location: Whiteville

PostPosted: Tue Mar 30, 2010 8:23 pm    Post subject: Help Physics! Reply with quote

A 1420-kilogram car, moving with a speed of 15.0 m/s, is on a flat, circular curve having a radius of 50.2 meters.

How much friction is needed to keep the car on the road?___________N

What is the coefficient of friction between the tires and the road?_______
Back to top
View user's profile Send private message
hepcj
Site Admin


Joined: 23 Jun 2007
Posts: 125

PostPosted: Tue Mar 30, 2010 10:29 pm    Post subject: Reply with quote

m =1420 kg
v= 15 m/s
r = 50.2

The force pushing the radially outward is
F = (m v^2)/r
= 1420 x (15^2)/50.2
= 6364.54 N

The car is kept on the track by the frictional force of the tyres opposing the centrifugal force F.
The frictional force is related to the weight by
F_fric = mu F_norm. where mu is the coefficient of friction.

Since the car is on a horizontal track, the magnitude of the normal force is:
F_norm = mg
1420 x 9.8 = 13916 N



Therefore, the coefficient of friction = 6364.54 N/13916 N = 0.46
Back to top
View user's profile Send private message Send e-mail
Delilah



Joined: 29 Mar 2010
Posts: 6
Location: Whiteville

PostPosted: Wed Mar 31, 2010 1:35 am    Post subject: Reply with quote

thanks so much, im having a time trying to grasp Physics
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Splung.com Physics Forum Forum Index -> Physics Help. Ask a Physics Expert All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


© Copyright 2010 Splung.com