PLEASE I AM GIVING MEDALS:)))
Emily leaves her physics book of mass 1 kg on the top of the table that is inclined at an angle of 20°. What is the acceleration of the book if the coefficient of kinetic friction between the book and the inclined plane is 0.3?

0.4 m/s2

0.5 m/s2

0.6 m/s2

0.7 m/s2

Question

PLEASE I AM GIVING MEDALS:)))
Emily leaves her physics book of mass 1 kg on the top of the table that is inclined at an angle of 20°. What is the acceleration of the book if the coefficient of kinetic friction between the book and the inclined plane is 0.3?

	
0.4 m/s2
	
0.5 m/s2
	
0.6 m/s2
	
0.7 m/s2

surry99 · Answer

Can you draw a Free body diagram for this problem?

anonymous · Answer

The book slides because there is a component of its weight acting along the slope (it means the vertical component of the normal force is less than the book's weight). 

That force, $wsin(\theta)$, is acting against kinetic friction, $f_k$, which is upward. So the net force is:

$F_{net}= wsin(\theta) - \mu_kN$

$ma = mgsin(\theta) - \mu_kmgcos(\theta)$

$a= g[sin(\theta) - \mu_kcos(\theta)]$

You can see that mass cancels and you can now figure out what acceleration you get with the slope and coefficient of kinetic friction you have.