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Physics A 10 Kg block lies on a smooth plane inclned at 51 degrees. What force parallel to the incline

JessiMen

New member
Jul 11, 2016
10
A 10 Kg block lies on a smooth plane inclined at 51 degrees. What force parallel to the incline would prevent the block from slipping?
 

MarkFL

Administrator
Staff member
Feb 24, 2012
13,775
Can you post your progress so far, so our helpers can see how best to help?
 

JessiMen

New member
Jul 11, 2016
10
oh I skipped this question in my review because i didnt know how to do it there is also a question b to it:

b) An object is dragged 6 m up a ramp under a constant force of 27 N applied at an angle of 32 degrees to the ramp. Calculate the work done
 

topsquark

Well-known member
MHB Math Helper
Aug 30, 2012
1,264
oh I skipped this question in my review because i didnt know how to do it there is also a question b to it:

b) An object is dragged 6 m up a ramp under a constant force of 27 N applied at an angle of 32 degrees to the ramp. Calculate the work done
...And what have you been able to do so far?

-Dan
 

JessiMen

New member
Jul 11, 2016
10
for this question nothing because i have no idea how to start it.
 

MarkFL

Administrator
Staff member
Feb 24, 2012
13,775
for this question nothing because i have no idea how to start it.
Okay, let's begin with a great tool used in physics called the free body diagram:

inclinefreebody.png

Okay, we wish to find the magnitude of the force $F$, which is equal in magnitude to $F_x$. We know the magnitude of $w$ (the weight vector) and we know $\theta$ where $\theta+\beta=\dfrac{\pi}{2}$...so can you use some trigonometry to relate $w$, $F_x$ and $\theta$?
 

Evgeny.Makarov

Well-known member
MHB Math Scholar
Jan 30, 2012
2,533
It seems to me that the figure would be clearer if $F_x$ and $F_y$ are renamed into $w_x$ and $w_y$ (and $w_x$ changes the direction). As I understand, $\vec{w}=\vec{w}_x+\vec{w}_y$. The component $\vec{w}_y$ of $\vec{w}$ is counterbalanced by the normal force $\vec{n}$ and $\vec{w}_x$ is counterbalanced by $\vec{F}$. But $\vec{F}$ does not have a $y$ component.