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Physics Mechanics- friction

Shah 72

Member
Apr 14, 2021
193
A book of mass 1.3 kg is on a plank of wood which is held at 16 degree to the horizontal. The coefficient of friction between the book and the plank is 0.45.
Find the size of the frictional force.
Iam getting the ans by using the formula F= coefficient of friction ×R
5.62N but the textbook ans is 3.58N.
Pls help
 

skeeter

Well-known member
MHB Math Helper
Mar 1, 2012
935
using 10 for g ...

$f = \mu \cdot mg\cos{\theta} = 5.62 \, N$

an aside ... since you're using a calculator anyway, why not use 9.8 for g? g = 10 is normally used when calculations are done by hand.
 

Shah 72

Member
Apr 14, 2021
193
using 10 for g ...

$f = \mu \cdot mg\cos{\theta} = 5.62 \, N$

an aside ... since you're using a calculator anyway, why not use 9.8 for g? g = 10 is normally used when calculations are done by hand.
Thank you!