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course Phy 121
November 15, 2011 at 9:59 a.m.Here is an older resubmission I forgot to submit. Looking at it, I know I missed something. I went back through the old intro problem sets, class notes, and queries and QAs and could not find something similar. I know I did something like this when the object was at rest on an incline, but cannot recall what to help me in remembering how to do the assignment.
Open Query 17point2
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course Phy 121
October 20, 2011 at 12:01 p.m.
________________________________________A 5 kg cart rests on an incline which makes an angle of 30 degrees with the horizontal.
• Sketch this situation with the incline rising as you move to the right and the cart on the incline. Include an x-y coordinate system with the origin centered on the cart, with the x axis directed up and to the right in the direction parallel to the incline.
The gravitational force on the cart acts vertically downward, and therefore has nonzero components parallel and perpendicular to the incline.
Sketch the x and y components of the force, as estimate the magnitude of each component.
What angle does the gravitational force make with the positive x axis, as measured counterclockwise from the positive x axis? Which is greater in magnitude, the x or the y component of the gravitational force?
answer/question/discussion:
???? I have looked and looked at this one and I just do not know the sine, cosine, etc. to even begin this. IS there a sample solution I can review to make an attempt at a solution here???
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-9.8 m/s^2 * 5 kg = 49 N
Angle for gravity = 90 deg - 30 deg = 60 deg.
x component = -49 N * cos(60 deg) = -24.5 N
y component = -49 N * sin(60 deg) = -42.4 N
mag = sqrt((-24.5 N)^2 + (-42.4 N)^2) = 49 N
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• Using the definitions of the sine and cosine, find the components of the cart's weight parallel and perpendicular to the incline.
answer/question/discussion:
x component = -49 N * cos(60 deg) = -24.5 N
y component = -49 N * sin(60 deg) = -42.4 N
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• How much elastic or compressive force must the incline exert to support the cart, and what is the direction of this force?
answer/question/discussion:
49 N
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• If no other force is exerted parallel to the incline, what will be the cart's acceleration?
answer/question/discussion:
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49 N / 5 kg = 9.8 m/s^2
@& Check Introductory Problem Set 5, which I believe was assigned previous to this.
That problem set gives you all the trigonometry you need for this course.*@
Open Query 17point2
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&#Very good responses. Let me know if you have questions. &#