MHB Friction Force: 1.3 kg Book on 16° Plank - Find the Answer!

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The discussion focuses on calculating the frictional force acting on a 1.3 kg book on a 16° inclined plank with a friction coefficient of 0.45. The initial calculation yields a frictional force of 5.62 N using the formula F = coefficient of friction × R, but the textbook states the answer is 3.58 N. The discrepancy arises from the value of gravitational acceleration (g) used in the calculations; while 10 m/s² is common for hand calculations, using 9.8 m/s² is more accurate with a calculator. The correct formula to find the frictional force is f = μ × mg cos(θ). The conversation emphasizes the importance of using the appropriate value for g to achieve accurate results.
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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
 
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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.
 
skeeter said:
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!
 
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