Coefficient of Friction Created for CVCA Physics By

Coefficient of Friction Created for CVCA Physics By Dick Heckathorn 19 November 2 K + 4

Table of Contents 3 4 5 7 Coefficient of Friction Table Force of ground on vehicle μ of block sliding on table μ of block sliding down ramp

Definitions Coefficient of friction (µ) is defined as the force of friction divided by the normal force. F F N N Ff Ff Fe on block

Surface Rubber on asphalt, dry Rubber on asphalt, wet Rubber on ice Rubber on concrete, dry Rubber on concrete, wet Steel on steel – dry Steel on steel – lubricated Steel on ice μ 1. 07 0. 95 0. 005 1. 02 0. 97 0. 41 0. 12 0. 01

Force of Surface on Explorer Weight Ford Explorer 26, 000 N Coefficient of friction rubber on asphalt dry - 1. 07 wet - 0. 95 ice - 0. 005 Fapplied dry = 1. 07 x 26, 000 N = 27, 820 N Fapplied wet = 0. 95 x 26, 000 N = 24, 700 N Fapplied ice =. 005 x 26, 000 N = 130 N

Analysis – Block on Table The Problem What is the coefficient of friction of a block sliding on a table?

Analysis – Block on Table Pull block at. Force constant Force Friction (F ) = =(μ) Normal (F Find coefficient of Force ofofearth onfriction block f= N) speed FN = 12. 48 N F f = 4. 5 N Fe on B = 12. 48 N F on B = 4. 5 N

Finding Coefficient of Friction of Block on Ramp Created for CVCA Physics By Dick Heckathorn 6 December 2 K+3

Analysis – Block on Ramp What is the coefficient of friction of a block sliding on a ramp?

Analysis – Block on Ramp Apparatus - Meter sticks (2) - Block with grove to fit over meter stick - scales to find weight of block

Analysis – Block on Ramp Procedure Place block on meter stick. Lift the meter stick until the block slides down the ramp at constant speed. Determine the angle of the meter stick with horizontal. Calculate the coefficient of friction.

Block sliding atthe speed Finding angle Finding coefficient of fricton μ The Measurements Fconstant and F N f FN = 1. 134 N θ 36. 8 cm 1 m Ff = 0. 449 N θ Fe on B = 1. 22 N

That’s all folks!

than Portland Less than More Cement 30 mi/hr Dry Road Surface New, Sharp 0. 8 - 1. 2 0. 7 – 1 Traveled 0. 6 - 0. 8 0. 6 – 0. 75 Traffic Polished 0. 55 - 0. 75 0. 5 – 0. 65 Wet Road Surface New, Sharp 0. 5 – 0. 8 0. 4 – 0. 75 Traveled 0. 45 - 0. 7 0. 45 – 0. 65

Asphalt Less than More than or Tar 30 mi/hr Dry Road Surface New, Sharp 0. 8 - 1. 2 0. 65 – 1 Traveled 0. 6 - 0. 8 0. 55 – 0. 65 Traffic Polished 0. 55 - 0. 75 0. 45 – 0. 65 Excess Tar 0. 5 – 0. 6 0. 35 – 0. 6 Wet Road Surface New, Sharp 0. 5 – 0. 8 0. 45 – 0. 75 Traveled 0. 45 - 0. 7 0. 4 – 0. 65 Traffic Polished 0. 45 - 0. 65 0. 4 – 0. 6

Less than More than Gravel 30 mi/hr Dry Road Surface Pack, Oiled 0. 55 – 0. 85 0. 5 – 0. 8 Loose 0. 4 - 0. 7 0. 4 – 0. 7 Wet Road Surface Pack, Oiled 0. 4 – 0. 8 0. 4 – 0. 6 Loose 0. 45 - 0. 75 0. 45 – 0. 75

Less than More than Gravel 30 mi/hr Dry Road Surface Ice Smooth 0. 1 – 0. 250. 07 – 0. 2 Snow Packed 0. 3 - 0. 55 0. 35 – 0. 55 Snow Loose 0. 1 – 0. 250. 1 – 0. 2 Wet Road Surface Ice Smooth 0. 5 – 0. 1 0. 05 – 0. 1 Snow Packed 0. 3 - 0. 6 0. 3 – 0. 6 Snow Loose 0. 3 - 0. 6 0. 3 – 0. 6

That is all, it is all!