# Does mass affect the value of the coefficient of friction?I have a lab that's due this Friday and its to find the coefficient of kinetic friction.the materials i used for this lab is : Newton...

Does mass affect the value of the coefficient of friction?

I have a lab that's due this Friday and its to find the coefficient of kinetic friction.
the materials i used for this lab is : Newton spring scale, The wood mass is 0.2724kg, Standard masses i did is 0.200kg, 0.400kg, 0.500kg and 0.700kg; and i used sandpaper for the wood to slide across in a uniform motion.
The total mass i have is 0.2724kg, 0.4724kg, 0.6724kg, 0.7724kg, and 0.9724.
The Fnormal: 2.67N for 0.2724kg, 2.86N for 0.4724kg, 3.06N for 0.6724kg, 3.16N for 0.7724kg, and 3.36N for 0.9724kg.
My average Fapplied is 1.625N, 2.825N, 4.50N, 5.125N, and 6.5N.

yaser4621 | eNotes Newbie

Posted on

I have a lab that is sling the following:

Design a procedure and find the values for the coefficients of kinetic friction and maximum static friction.

I have to find out how does the coefficient depend on mass (horizontal; at least 5 different masses)

My question is how would I find the coefficients of kinetic friction and maximum static friction

krishna-agrawala | College Teacher | (Level 3) Valedictorian

Posted on

Coefficient of friction does not depend on the mass applied. it depends only on the area and nature of two surfaces in contact. However, the frictional force exerted does depend on the the normal force, which in turn may depend on the mass.

The coefficient of friction is defined as normal force divides by frictional force. Thus:

Coefficient of friction = Fnormal/Fapplied

As per the data of the experiment conducted by you, which you have given in your question, the values of Fnormal are:

(1) 2.67 (2.67) N, (2) 4.65 (2.86) N, (3) 6.60 (3.06) N, (4) 7.58 (3.16) N, and (5) 9.54 (3.36) N.

Please note some of the values of Fnormal calculated by you are not correct. Fnormal is equal to mass multiplied by acceleration due to gravity (9.81). I have given above the correct values with values calculated by you in parenthesis.

And the correspoding value of Fapplied are:

(1) 1.625 N, (2) 2.825 N, (3) 4.50 N, (4) 5.125 N, and (5) 6.5 N.

Based on these values we can calculate 5 different values of coefficient of friction as follows:

(1) Coefficient of friction = Fapplied/Fnormal = 1.625/2.67 = 0.61

(2) Coefficient of friction = Fapplied/Fnormal = 2.825/4.65 = 0.61

(3) Coefficient of friction = Fapplied/Fnormal = 4.50/6.60 = 0.68

(4) Coefficient of friction = Fapplied/Fnormal = 5.125/7.58 = 0.68

(5) Coefficient of friction = Fapplied/Fnormal = 6.5/9.54 = 0.68