Login

Search the forums now!

Welcome, Guest. Please login or register.

April 20, 2024, 08:12:37 am
Pages: [1] 2 3   Go Down

Author Topic: friction on a banked road  (Read 4489 times)  Share 

0 Members and 1 Guest are viewing this topic.

you0006

  • Victorian
  • Trendsetter
  • **
  • Posts: 101
  • Respect: 0
friction on a banked road
« on: June 12, 2011, 12:40:27 pm »
0
Hi guys,
just been reading another post and this came up...

Is there a formula that gives you Fnet on a banked road with friction?

Logged

yawho

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 213
  • Respect: +2
Re: friction on a banked road
« Reply #1 on: June 12, 2011, 12:51:38 pm »
0
yes
At the design speed:
vert comp, net force=Ncos-mg=0
hori comp, net force=Nsin=mv^2/r

greater than the design speed: friction f
vert comp, net force=Ncos-mg-fsin=0
hori comp, net force=Nsin+fcos=mv^2/r

less than the design speed: friction f
vert comp, net force=Ncos-mg+fsin=0
hori comp, net force=Nsin-fcos=mv^2/r
Logged

Shark 774

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 261
  • Respect: +1
Re: friction on a banked road
« Reply #2 on: June 12, 2011, 01:47:54 pm »
0
Does anybody have a specific example of where you'd use this?
Logged

yawho

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 213
  • Respect: +2
Re: friction on a banked road
« Reply #3 on: June 12, 2011, 02:04:24 pm »
0
a circular corner of radius 10 m is banked at 15 degree with the horizontal. find the speed that a car can make the turn without friction to assist the turn. If the 800-kg car travels at 5 m/s higher than that speed, what friction between the tyres and the road is required for the car to make the turn?
Logged

Vincezor

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 332
  • Respect: +11
  • School: Glen Waverley Secondary College
  • School Grad Year: 2011
Re: friction on a banked road
« Reply #4 on: June 12, 2011, 02:10:35 pm »
0
Quote from: yawho on June 12, 2011, 02:04:24 pm
a circular corner of radius 10 m is banked at 15 degree with the horizontal. find the speed that a car can make the turn without friction to assist the turn. If the 800-kg car travels at 5 m/s higher than that speed, what friction between the tyres and the road is required for the car to make the turn?

Sorry do you have the answer to that? I got though I have no idea! :S
« Last Edit: June 12, 2011, 03:09:36 pm by Vincezor »
Logged
2010: Systems Engineering 44            

2011: Specialist Mathematics 37 | Mathematical Methods (CAS) 43 | Physics 39 | Chemistry 42 | English 41

ATAR: 98.50

2012: Eng/Law @ Monash

luffy

  • Victorian
  • Forum Leader
  • ****
  • Posts: 520
  • Respect: +23
  • School Grad Year: 2011
Re: friction on a banked road
« Reply #5 on: June 12, 2011, 02:15:19 pm »
0
Quote from: yawho on June 12, 2011, 02:04:24 pm
a circular corner of radius 10 m is banked at 15 degree with the horizontal. find the speed that a car can make the turn without friction to assist the turn. If the 800-kg car travels at 5 m/s higher than that speed, what friction between the tyres and the road is required for the car to make the turn?

My answer was 6141N - though I'm likely incorrect. lol
Logged

moekamo

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 275
  • Respect: +4
Re: friction on a banked road
« Reply #6 on: June 12, 2011, 02:18:19 pm »
0
i got 5m/s for the first part, then 6211N for the second part, if this is right ill show my working :)
Logged
2nd Year BSc/BEng @ Monash

xZero

  • Victorian
  • Forum Leader
  • ****
  • Posts: 898
  • Respect: +68
Re: friction on a banked road
« Reply #7 on: June 12, 2011, 02:31:09 pm »
0
v=5ms^-1 (should be easy to work out)

f=6212n for the second part , use fnet=mv^2/r to find the net force. Since the centripetal force(Fc) is not enough, there needs a friction force to push the car inward. Let friction force = F, we only need the horizontal component so take Fcos15. fnet=Fc+Fcos15. Fc can be found easily so now just solve for F
Logged
2009: Chinese SLA
2010: English, Maths method[45,A+ A+ A+], Specialist maths[44,A+,A,A+], Physics[40,A,A+,A+], Psychology Atar:94.75
2011-2015: Bachelor of Aerospace Engineering/Science @ Monash

Methods/Spesh/Physics tuition

yawho

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 213
  • Respect: +2
Re: friction on a banked road
« Reply #8 on: June 12, 2011, 02:46:06 pm »
0
approx 5900 N
Logged

Milkshake

  • Victorian
  • Trendsetter
  • **
  • Posts: 164
  • Respect: +1
Re: friction on a banked road
« Reply #9 on: June 12, 2011, 03:01:52 pm »
0
I got around 6505N. How come you just took v for the first part to be 5, and not like 5.176? Are we meant to round after each step or?
Logged

jinny1

  • Victorian
  • Part of the furniture
  • *****
  • Posts: 1328
  • .carpe diem
  • Respect: +105
  • School: Melbourne Dental School
Re: friction on a banked road
« Reply #10 on: June 12, 2011, 03:10:56 pm »
0
lol it's funny how everyone got different answers :P
Logged
:D :) ;D :D :) ;D :D :) ;D :D :) ;D :D :) ;D :D :) ;D                               

xZero

  • Victorian
  • Forum Leader
  • ****
  • Posts: 898
  • Respect: +68
Re: friction on a banked road
« Reply #11 on: June 12, 2011, 03:16:04 pm »
0
Quote from: Milkshake on June 12, 2011, 03:01:52 pm
I got around 6505N. How come you just took v for the first part to be 5, and not like 5.176? Are we meant to round after each step or?
I actually got 4.9497ms^-1, I just took v as 5 coz it looks neat (don't do this in an exam)
Logged
2009: Chinese SLA
2010: English, Maths method[45,A+ A+ A+], Specialist maths[44,A+,A,A+], Physics[40,A,A+,A+], Psychology Atar:94.75
2011-2015: Bachelor of Aerospace Engineering/Science @ Monash

Methods/Spesh/Physics tuition

Shark 774

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 261
  • Respect: +1
Re: friction on a banked road
« Reply #12 on: June 12, 2011, 03:18:04 pm »
0
Quote from: Vincezor on June 12, 2011, 02:10:35 pm
Quote from: yawho on June 12, 2011, 02:04:24 pm
a circular corner of radius 10 m is banked at 15 degree with the horizontal. find the speed that a car can make the turn without friction to assist the turn. If the 800-kg car travels at 5 m/s higher than that speed, what friction between the tyres and the road is required for the car to make the turn?

Sorry do you have the answer to that? I got though I have no idea! :S

I agree with this answer.
Logged

Vincezor

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 332
  • Respect: +11
  • School: Glen Waverley Secondary College
  • School Grad Year: 2011
Re: friction on a banked road
« Reply #13 on: June 12, 2011, 03:18:29 pm »
0
Okay here's what I did. Point out any mistakes I may have made :D





















EDIT: Trivial mistakes with variables :(
« Last Edit: June 12, 2011, 06:06:24 pm by Vincezor »
Logged
2010: Systems Engineering 44            

2011: Specialist Mathematics 37 | Mathematical Methods (CAS) 43 | Physics 39 | Chemistry 42 | English 41

ATAR: 98.50

2012: Eng/Law @ Monash

Shark 774

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 261
  • Respect: +1
Re: friction on a banked road
« Reply #14 on: June 12, 2011, 04:00:24 pm »
0
Quote from: Vincezor on June 12, 2011, 03:18:29 pm
Okay here's what I did. Point out any mistakes I may have made :D





















Agreed
Logged
Pages: [1] 2 3   Go Up