If an angle 45 degree, then how to calculate the another angle?

Indranil

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If you see the picture, you can see 45-degree angle between 3m and r =3, so how to calculate the angle to the right side of the point B?
 

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if its an elastic collision you can assume that angle of incidence is the angle of reflection...can you post the question?

actually on the mouse over its gives reference to circular motion...are you talking about the velocity component tangent to a radius?
 
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if its an elastic collision you can assume that angle of incidence is the angle of reflection...can you post the question?

actually on the mouse over its gives reference to circular motion...are you talking about the velocity component tangent to a radius?
Yes, you are right. Could you explain how to calculate the above-said angle? I am confused.
 
Yes, you are right. Could you explain how to calculate the above-said angle? I am confused.

of course!

so imagine something moving with uniform circular motion. When we say uniform circular motion, we mean that the magnitude of velocity is not changing as an object rotates in a circle HOWEVER, it's DIRECTION is, so we say that an object undergoing this uniform circular motion is accerlerating (because it is changing direction, a result of velocity being a vectory quantity ie magnitutde AND direction).

Armed with that background knowledge, at every point in it's circle, the object will moving in a different direction. So what we do is say that the DIRECTION it is moving in is TANGENT to the motion's radius at any givent point.

So when you draw a line to the radius of motion from the centre, and a line TANGENT to the point where IT MEETS THE RADIUS OF MOTION, you end up with PERPENDICULAR lines. Do you know what angle PERPENDICULAR lines form? If you do, then you know your answer! :)
 
of course!

so imagine something moving with uniform circular motion. When we say uniform circular motion, we mean that the magnitude of velocity is not changing as an object rotates in a circle HOWEVER, it's DIRECTION is, so we say that an object undergoing this uniform circular motion is accerlerating (because it is changing direction, a result of velocity being a vectory quantity ie magnitutde AND direction).

Armed with that background knowledge, at every point in it's circle, the object will moving in a different direction. So what we do is say that the DIRECTION it is moving in is TANGENT to the motion's radius at any givent point.

So when you draw a line to the radius of motion from the centre, and a line TANGENT to the point where IT MEETS THE RADIUS OF MOTION, you end up with PERPENDICULAR lines. Do you know what angle PERPENDICULAR lines form? If you do, then you know your answer! :)
I understand your point but still, I don't understand how to find the angle to the right side of the pint B.
 
I understand your point but still, I don't understand how to find the angle to the right side of the pint B.

sorry for the delay!

so you found angle in the interior of the triangle. You you know that is 45 degrees.

based on what we just talked about, the angle between that 45 and b has to be 90 degrees.

One side of a straight line has to add up to 180 degrees.

So if you know you have one side of a straight line, and that side is divided in 3 sections, and we know what two of the sections are then can you find the third?

aka we know all 3 of those angles have to add up to 180...so a little bit of algebra and your done! :)
 
sorry for the delay!

so you found angle in the interior of the triangle. You you know that is 45 degrees.

based on what we just talked about, the angle between that 45 and b has to be 90 degrees.

One side of a straight line has to add up to 180 degrees.

So if you know you have one side of a straight line, and that side is divided in 3 sections, and we know what two of the sections are then can you find the third?

aka we know all 3 of those angles have to add up to 180...so a little bit of algebra and your done! :)
Ok, I take the straight line B which contains 3 sections a, b, and c.
a + b + c =180 We know a = 45 degree (the left side angle to the point B of the straight line), b is the middle angle and c is the right side angle). as I know a = 45 so how to find c? How to calculate?
 
Ok, I take the straight line B which contains 3 sections a, b, and c.
a + b + c =180 We know a = 45 degree (the left side angle to the point B of the straight line), b is the middle angle and c is the right side angle). as I know a = 45 so how to find c? How to calculate?
Do you see that you are dealing with a right-angled triangle?
 
Look at where the yellow line meets the horizontal line.
Do you see the little yellow square?
 
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Look at where the yellow line meets the horizontal line.
Do you see the little yellow square?
please don't get me wrong. I think you don't understand my question. Again, I have uploaded an edited image where you can see which angle I have been talking about? Please see and help me to calculate the angle.
 

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… I think you don't understand my question …
I think we do understand your question, and I see that you've been told twice how to answer it.

You told us that you understand the three angles must add up to 180°.

You told us that you understand the "left" angle is 45° and the "center" angle is 90°.

45° + 90° + X° = 180°

Why can you not find X?

You were also told (twice) that the angle you're looking for is the same as the "left" angle. You posted that you understand this.

45° = X°

Why can you not find X?

I think sometimes you don't pay attention. I also think you don't understand some things in our replies, but you don't tell us. :idea: We cannot read your mind.




… that angle of incidence is the angle of reflection …

Yes, you are right …

… Do you know what angle PERPENDICULAR lines form? If you do, then you know your answer! …

I understand your point …

… we know all 3 of those angles have to add up to 180 …
… How to calculate?
 
if its an elastic collision you can assume that angle of incidence is the angle of reflection
Could you explain please the idea of 'angle of incidence is the angle of reflection'?
Here in the picture above, Could you tell me which angle is the angle of incidence and which one is the angle of reflection?
 
Could you explain please the idea of 'angle of incidence is the angle of reflection'?
Here in the picture above, Could you tell me which angle is the angle of incidence and which one is the angle of reflection?

a billiard ball bouncing off a rail.
the angle it approaches the rail is incidence, the angle it leaves is reflection.
 
Could you explain please the idea of 'angle of incidence is the angle of reflection'? …
This describes the angles formed when an object bounces off a surface (like a beam of light). In the images below, note the direction of each vector (shown by arrows). The incoming vector is the incidence ray, and the outgoing vector is the reflection ray.

I believe the following is the most-common definition for angle of incidence and angle of reflection (the two angles are measured with respect to a line perpendicular to the mirror -- called the "normal" line -- shown below as a dotted line):

angINCrefl1.JPG


But I regularly see this definition, too.

angINCref2.JPG


In your exercise, you have a 45-90-45 right triangle. Therefore, all four angles are 45° (see first image above), so it doesn't matter which definition you use, with your triangle.

If you're concerned about which definition to use with other triangles, then you could use the most-common definition or you could ask the exam administrator to confirm their definition. :cool:
 
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