sanukee
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#1
Report Thread starter 11 years ago
#1
im really confused on how i go about this question and how the force diagram and triangle will look like can you please help??


A ball of mass 9.3kg rests on a ramp that makes an angle of 18◦ with
the horizontal. It is held in place by a rope that makes an angle of 42◦
with the horizontal, as shown in the diagram. Assume that the only
forces acting on the ball are its weight, the tension in the rope and the
normal reaction from the ramp. Take the magnitude of the
acceleration due to gravity to be g = 10ms−2.

1. Draw a force diagram for the forces acting on the ball, defining
the symbols that you use to denote the forces, and indicating the
sizes of the angles between the forces.

2. Draw a corresponding triangle of forces, indicating the sizes of the
angles.

3. Use the triangle of forces to find the magnitudes of the tension in
the rope and the normal reaction from the ramp, to the nearest
newton.
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generalebriety
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Here's the diagram, without forces. I'll leave you to put the forces on - the question tells you which ones are acting.
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sanukee
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#3
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im not sure but have i done this correctly??


...and the angle between 42 degrees and 18 derees is a right angle??
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Glutamic Acid
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Doesn't the weight act directly vertical? And the normal reaction at right angles to the ball.
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sanukee
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#5
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so it would look like this?

i dont understand 'And the normal reaction at right angles to the ball.'
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Maths Buster
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#6
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The weight acts straight down.
The normal reaction makes an angle of 18 degrees with the upward vertical.
The tension makes an angle of 48 degrees with the upward vertical.
And so:
Draw a line downwards to represent the weight. Then go off to the right, making an angle of 18 degrees with the upwards vertical. Finally, go to the left, making an angle of 48 degrees with the upward vertical. When you hit your weight line, you'll have your triangle of forces.
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Glutamic Acid
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#7
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I've tried drawing a diagram:
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sanukee
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#8
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im confused would i use the oppersite angles in the triangle?
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sanukee
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#9
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according to Glutamic Acid i have done my diagram wrong hang on......... i will do it again
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Glutamic Acid
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#10
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I think the normal reaction force should be acting in the other direction, since it's a force from the ramp. Seems alright apart from that.
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sanukee
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#11
Report Thread starter 11 years ago
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this is my version
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