Finding the force on an inclined plane

In summary, the conversation discusses the calculation of the force required to accelerate a 150.0 kg crate up an inclined plane at a 30° angle with no friction. The net force is determined by subtracting the force due to gravity from the applied force, resulting in an equation of F_net = m(7.1 + g/2). Using the values of mass and gravity, the resulting force is found to be 1800 N.
  • #1
cbarker1
Gold Member
MHB
349
23
Dear Everybody,

What force (in N) must be applied to a 150.0
kg crate on a frictionless plane inclined at 30° to cause an acceleration of 7.1 m/s2 up the plane?

Work:
I know the sum of the force in the x direction must be equal to mass multiply by acceralation.Thanks
Carter
 
Mathematics news on Phys.org
  • #2
Let's assume the applied force is parallel to the incline plane...and so we require:



What is the magnitude of the force due to gravity () along the plane?
 
  • #3
MarkFL said:
Let's assume the applied force is parallel to the incline plane...and so we require:



What is the magnitude of the force due to gravity () along the plane?

I believe it is .
 
  • #4
Cbarker1 said:
I believe it is .

Think about the cases where the plane is either vertical or horizontal...does the cosine function makes sense?
 
  • #5
MarkFL said:
Think about the cases where the plane is either vertical or horizontal...does the cosine function makes sense?

NO, it does not make any sense. so it must be sine function.
 
  • #6
Cbarker1 said:
NO, it does not make any sense. so it must be sine function.

Yes, it is the sine function...here's a free-body diagram:

free_body.svg.png


What do you find for ?
 
  • #7
MarkFL said:
Yes, it is the sine function...here's a free-body diagram:
What do you find for ?

Is that correct?

Sorry, I have misread the question that there is a force pushing it up the inclined plane.
 
  • #8
Cbarker1 said:
Is that correct?

Sorry, I have misread the question that there is a force pushing it up the inclined plane.

That's correct, although we know:



And so we may write:



Next, use:



So, what do you get?
 
  • #9
the answer is 1800 N
 
  • #10
Cbarker1 said:
the answer is 1800 N

Yes, I concur. (Yes)
 
  • #11
I did the problem correctly.
 
Back
Top