Skid Friction
Skid Friction

Coefficient of static friction with known tangential acceleration?
A car traveling on a flat (unbanked) circular track accelerates uniformly from rest with a tangential acceleration of 1.45 m/s2. The car makes it one quarter of the way around the circle before it skids off the track. Determine the coefficient of static friction between the car and track from these data.
I put this on my watch list, but forgot about it. Hope its not too late! Since the problem gives that the distance the car makes around the track is one quarter of the way, and the circumference of a circle is C = 2πr, then:
Δx = 0.25(2πr)
= 0.5πr------> equation (1)
Now from Newton's 2nd law, the net centripetal force (which is caused by friction) on the car is:
∑F(c) = ma(c) = μmg
Centripetal acceleration is equal to v² / r, so the centripetal force equation becomes:
mv² / r = μmg
v = √μgr------- equation (2)
We can substitute (1) and (2) into the time independent kinematics equation and solve for μ :
v² = v₀² + 2aΔx
(√μgr)² = 0 + (2 x 1.45m/s² x 0.5πr)
μgr = 1.45πr
μ = 1.45π / 9.80m/s²
= 0.465
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Gilsson UBM Portable Car Non-Skid Friction Beanbag Dashboard Mount for Garmin, TomTom, Magellan and more
List Price: $26.95
Sale Price: Too low to display
Average Rating: 
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Gilsson Universal Portable Friction Beanbag Mount Base, works with existing suction cup mounts for iPod iPhone Smartphone GPS PDA XM devices - Very Stable and Non-Slippery. CA and MN laws prohibit the use of windshield mount.
This Gilsson portable beanbag mount is a great base mount for your GPS, MP3 Player, smart phone, or most any portable electronic device. Weighing about two pounds, it's just heavy enough to make sure your electronic device stays put, even with sudden or abrupt maneuvering. It's an ideal choice for drivers in states where the use of windshield suction cup mounts is illegal, and for those who prefer a mount that can quickly be moved out of the way. It won't leave any ugly adhesive residues on your dashboard, and allows you to hide the GPS from thieves when exiting your vehicle. Note: this beanbag mount requires the use of a fixed marine, dashboard or suction cup pedestal, which is secured to the the detachable plate on the beanbag mount base. Works like a charm with Garmin, Magellan, Mio, TomTom, Mio, Lowrance, Motorola, Apple iPod, iPhone, Blackberry, Cell Phone, MP3 or other portable electronics devices. What's in the Box Gilsson UBM Portable Car Non-Skid Friction Beanbag Dashboard Mount, User's Manual
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Gilsson UBM-1 Portable Car Non-Skid Friction Beanbag Dashboard Mount
List Price: $29.95
Sale Price: $8.98
Average Rating: 
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Compatible with suction cup mount/bracket of most portable Garmin, TomTom, Magellan, Mio, Navman, Lowrance GPS, iPod iPhone, Smartphone, PDA, XM receivers. The portable mount features anti-skid material and it is weighted to prevent any sliding or tilting during turning, braking and normal vehicle maneuvers. We have tested our mount against three other competitive products and found our mount to be most stable. Please note, this item is the portable beanbag mount at the bottom and does not include the suction cup pedestal and the universal GPS holder nor the GPS themselves. Those items are included in the 2nd and 3rd pictures for illustration purposes only.
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Garmin Beanbag for Portable Friction Mount for Garmin GPS Units (Beanbag Only - Mount not Included)
List Price: $34.99
Sale Price: $16.99
Used From: $17.30
Average Rating: 
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Everything has its place and so does your StreetPilot GPS unit. Attach your GPS unit to this non-skid friction mount and don't worry about it. It can't slide off when you are driving in traffic, so it sits securely on your dash, console, or any other surface. And you can remove it for use in another vehicle. This mount works with the iQue 3600, GPS ll/ GPS V, GEKO 101/201, EMAP Series, STREEPILOT, ETREX and RINO 110/120.
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CM012+GN014-SPH+CC005-IP: Deluxe Non-Skid / Friction Style Weighted Dashboard Mount with Safety Hook for Apple iPhone 3G and Original Apple iPhone
Sale Price: $24.99
Average Rating: 
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# ***PRODUCT AS SHOWN IN PICTURE. DOES NOT INCLUDE IPHONE.***
# ***IPHONE MUST BE NAKED/WITHOUT A CASE TO FIT INTO THE CRADLE/HOLDER.***
# U-Shaped rim design more optimal than fully enclosed Non-Skid mounts as it allows you to lower the windshield pedestal for optimal viewing
# Ideal for use with the iPhone 3G GPS function
# 80mm suction disc acts as the base for your windshield suction pedestal
# Easily transferred from one vehicle to another
# Includes CM012 dashboard Mount, CM014-2 Travelmount® mini windshield suction pedestal, and CC005-IP passive custom cradle for iPhone 3G and Original iPhone
# Travelmount® mini windshield suction pedestal is included with this model
# Patents Pending
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CM012+GN014-SPH+APTTGO520: Deluxe Non-Skid/Friction Style Weighted Dash Mount with Safety Hook for TomTom GO 520 530 720 730 920 930 Edition GPS
Sale Price: $24.99
Average Rating: 
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# Ideal for use with portable GPS / PND devices
# 80mm suction disc acts as the base for your windshield suction pedestal
# Easily transferred from one vehicle to another
# Includes CM012 Dash Mount, CM014-2 Travelmount mini windshield suction pedestal, and APTTOGO adapter plate for TomTom GO devices (520 530 720 730 920 930 Edition)
# Travelmount® mini windshield suction pedestal is included with this model
# ARKON also offers other bundles that include a windshield suction pedestal for your Magellan or Garmin GPS device
# Patent Pending
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Anti-Skid Friction Dash Mount + Large Holder for MOST TomTom, Garmin, Nextar, and Magellan GPS Units & Most Large Mobile Phones, PDAS, and Mp3 Players with up to a 7 Inch Screen!
Sale Price: $9.99
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For any GPS with up to a 7" screen!
The most convenient mounting accessory for your portable GPS/Mobile Phone device. Turn your windshield mounted GPS/Mobile device into a dash mounted GPS/Mobile device.
The dash mount contours to the top of your dashboard allowing it to work on uneven and textured surfaces, while the anti-skid underside keeps your device from sliding.
The dash mount combines the physics of weight distribution along with high-tech anti-skid materials creating a solid mounting base for your device.
The dash mount works with devices up to several pounds using the windshield suction mount that is sold with most popular GPS/Mobile devices.
With no fastening and tool-free installation, the dash mount can easily be moved from vehicle to vehicle.
Works with any GPS brand that uses a suction cup mount (Garmin, TomTom, Magellan, etc...)
High Quality Brand NEW Universal GPS/MP3/Phone Car Mount
Universal design works with all types of iPods/MP3 Players/PDAs/GPS units and cell phones.
Firmly mounts onto Windshield / Dash / AC Vent and can be removed easily.
Extra firm pedestal absorbs vibrations and provides a stable viewing platform.
A vent pothook and 360 degree rotating support holder included for easy viewing.
Quick release button extends arms automatically.
Easily adjusts to your desired viewing angle for optimal viewing.
No extra tools needed, easy to install.
Convenient, reliable and easy to use.
Width can be expanded with a button. Range: 3"~7"
Can be used vertically or horizontally.
This item is 100% New! Never used. One Year Warranty by Seller.
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Anti-Skid Friction Dash Mount + Large Holder for MOST TomTom, Garmin, Nextar, and Magellan GPS Units & Most Large Mobile Phones, PDAS, and Mp3 Players with up to a 7 Inch Screen!
Sale Price: $9.49
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For any GPS with up to a 7" screen!
The most convenient mounting accessory for your portable GPS/Mobile Phone device. Turn your windshield mounted GPS/Mobile device into a dash mounted GPS/Mobile device.
The dash mount contours to the top of your dashboard allowing it to work on uneven and textured surfaces, while the anti-skid underside keeps your device from sliding.
The dash mount combines the physics of weight distribution along with high-tech anti-skid materials creating a solid mounting base for your device.
The dash mount works with devices up to several pounds using the windshield suction mount that is sold with most popular GPS/Mobile devices.
With no fastening and tool-free installation, the dash mount can easily be moved from vehicle to vehicle.
Works with any GPS brand that uses a suction cup mount (Garmin, TomTom, Magellan, etc...)
High Quality Brand NEW Universal GPS/MP3/Phone Car Mount
Universal design works with all types of iPods/MP3 Players/PDAs/GPS units and cell phones.
Firmly mounts onto Windshield / Dash / AC Vent and can be removed easily.
Extra firm pedestal absorbs vibrations and provides a stable viewing platform.
A vent pothook and 360 degree rotating support holder included for easy viewing.
Quick release button extends arms automatically.
Easily adjusts to your desired viewing angle for optimal viewing.
No extra tools needed, easy to install.
Convenient, reliable and easy to use.
Width can be expanded with a button. Range: 3"~7"
Can be used vertically or horizontally.
This item is 100% New! Never used. One Year Warranty by Seller.
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Friction mount
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Garmin 010-10613-00 Friction mount Garmin International Inc. is a subsidiary of Garmin Ltd. the global leader in satellite navigation. Since 1989, the Garmin group of companies has designed, manufactured, marketed and sold navigation, communication and information devices and applications – most of which are enabled by GPS technology. Garmin's products serve automotive, mobile, wireless, outdoor recreation, marine, aviation, and OEM applications. Garmin employees are in the air, on the water, in the woods, behind the wheel and on the run. And they're always thinking of ways to adapt and improve. At Garmin, you never know how the next great idea will be born. But you know it's coming soon. Portable dash mount with non-skid material design keeps your Garmin unit securely in place with no hardware or adhesive mounting necessary. Weighty, non-skid mount design conforms to your dash's contour for a sleek look and solid fit. Fully portable for use in multiple vehicles. Includes 12/24 volt cigarette lighter adapter. Garmin 010-10613-00 Friction mount Features:
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Garmin Portable Friction Mount
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Portable Friction Mount This new portable friction mount features a non-skid bottom and pliable base to keep the mount secure on your dashboard. The integrated arm can be folded down for easy storage in an automobile console or in luggage. Plus, the portable friction mounts sleek new design looks great on any dashboard!
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ARKON CM012 Deluxe Non-Skid Friction Dashboard Mount with Safety Hook
$18.99
Type: Mount Features: Universal - For use with ALL windshield suction pedestals offered by ARKON or other manufacturers Innovative design includes optional adhesive safety hook that attaches to loop on dash mount Anti-skid material on base prevents movement of mount The perfect alternative mount for California and Minnesota drivers where windshield mounts are banned U-Shaped rim design
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Gilsson UBM Non-Skid Neoprene Portable Friction Beanband Dashboard Mount
$17.99
Type: Mount Compatibility: Apple iPod, iPhone, Zune Media Player, Blackberry, Motorola Razr, MP3 Player Garmin color eTrex, Nuvi 200 200W 350 360 650 660 750 760 series (Comparable to Garmin 010-10306-00) Magellan RoadMate GPS Maestro 3100 3140 3200 3250 4000 4040 4050 4250, RoadMate 2000 Mio C230 C720T TomTom One, OneXL, Go 720 920T Lowrance Navigon Features: Non-skid Neoprene Design, Portable Beanbag, Leaves no residue. More Stable than Garmin and other brands Great Portable Base for your Garmin Magellan Mio Lowrance Tom GPS, Apple iPod, iPhone, Blackberry Also great for your Blackberry, GPS, Palm, Zune, Smartphones, Media Player and MP3 devices Similar to Garmin Part # 010-10908-00 and 010-10306-00 A
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ARKON TT112 Non skid/ Friction Style Weighted Dash mount for TomTom Go series
$24.99
Type: Mount Specifications: 80mm suction disc acts as the base for your windshield suction pedestal Deluxe Non skid/ Friction Style Weighted Dash mount for TomTom Go series Compatible with TomTom GO 520, 530, 720, 730, 920, 930 Features: Innovative design includes optional adhesive safety hook that attaches to loop on dash mount Anti-skid material on base prevents movement of mount The perfect alternative mount for California and Minnesota drivers where windshield mounts are banned U-Shaped rim design more optimal than fully enclosed Non-Skid mounts as it allows you to lower the
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Arkon-Cellular - Arkon Deluxe Non-Skid Friction Dashboard Mount With Safety Hook
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cm012 Deluxe Non-skid Friction Dashboard Mount's Innovative Design Includes Optional Adhesive Safety Hook That Attaches To Loop On Dashboard Mount. Its Anti-skid Material On Base Prevents Movement Of Mount. The Perfect Alternative Mount For California And Minnesota Drivers Where Windshield Mounts Are Banned. *Additional Information: ideal For Use With Portable Gps / Pnd Devices anti-skid Material On Base Prevents Movement Of Mount innovative Design Includes Optional Adhesive Safety Hook That Attaches To Loop On Dashboard Mount anti-skid Material On Base Prevents Movement Of Mount [Y95348] UPC: 047407510121 UNSPC: 31162300 8.25L x 7W x 1H 2.1 LB
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Arkon-Cellular - Arkon Gn112 Deluxe Non-Skid/Friction Style Weighted Dashboard Mount With Safety Hook
$23.45
gn112 Deluxe Non-skid/friction Style Weighted Dashboard Mount Has Innovative Design Includes Optional Adhesive Safety Hook That Attaches To Loop On Dashboard Mount. Its 80mm Suction Disc Acts As The Base For Your Windshield Suction Pedestal. *Additional Information: easily Transferred From One Vehicle To Another anti-skid Material On Base Prevents Movement Of Mount [Y95352] UPC: 047407501129 UNSPC: 31162300 11L x 7W x 4H 2.25 LB
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GPS - PNDS PRTBL FRICTION MOUNT NON SKID RETRACTABLE ARM 010-11280-00
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Garmin Dashboard Friction Mount - Portable, Non-Skid, Auto Lighter Adapter, for C310/C320/C330/C340
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Garmin Dashboard Friction Mount - Portable, Non-Skid, Auto Lighter Adapter, for C310/C320/C330/C340
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