Force Applied at an Angle to an Object on Frictionless Surface

  • Thread starter jpsmith394
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  • #1

Homework Statement


The horizontal surface on which the block slides is frictionless. If F = 20 N and M = 5.0 kg, what is the magnitude of the resulting acceleration of the block? The force is applied 30° to the horizontal.


Homework Equations


[itex]F=ma[/itex]


The Attempt at a Solution


I began by ignoring the weight and normal force in the vertical axis (y-axis) because the surface is frictionless. Then my next step is to separate the force into compenets with [itex]F_{x}=Fcos\theta[/itex]

Therefore:
[itex]ƩF_{x}=Fcos\theta = ma_{x}[/itex]

So:
[itex]a_{x}=\frac{Fcos\theta}{m}[/itex]

And using the given numbers I got a solution of 3.46[itex]\frac{m}{s^2}[/itex]
But the online system I am using shows the correct answer as 7.5[itex]\frac{m}{s^2}[/itex]
 

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Answers and Replies

  • #2
tiny-tim
Science Advisor
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hi jpsmith394! welcome to pf! :smile:

erm :redface: … you forgot the other F, in front! :wink:
 
  • #3
hi jpsmith394! welcome to pf! :smile:

erm :redface: … you forgot the other F, in front! :wink:

Oh gosh I see now, I was just stuck thinking it was just a single force :surprised

Thanks,
James
 

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