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### Course: MCAT>Unit 9

Lesson 1: Vectors and scalars

# Visualizing vectors in 2 dimensions

Learn about two-dimensional vectors, their magnitude and direction. Discover how to add vectors visually and break them down into horizontal and vertical components. This technique transforms complex two-dimensional problems into manageable one-dimensional problems, a key strategy in classical mechanics.
Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

## Want to join the conversation?

• I don't think it's a good idea for him to use a calculator when we won't have that option on the MCAT. This needs to mirror the MCAT.
• This content was not created specifically for the MCAT, only included in this section because it is conceptually relevant.
• I'm a little confused as to why this is in the MCAT section. How are vectors used in medicine?
• Just look at it this way. You need this knowledge for the MCAT and you need a good mcat to study medicine.
• [5]sin(36.8699) = -3.687
[5]cos(36.8699) = 3.377
Where did he get his answers from? I am so confused...
• Sal merely made a mistake when writing out the angle in the sine and cosine problems.

You did set up the problem correctly though. Make sure that your graphing calculator is in degrees and not radians. (They give two completely different answers).

You might want to look into memorizing the typical right triangles that will appear on the MCAT. These triangles are the 3-4-5 triangles and the 5-12-13 triangles. It is said that multiples of these two triangles (the 3-4-5 one more than the other) appears on the MCAT the most (ex. a 6-8-10 triangle would have the same angles as the 3-4-5, etc). Also look into memorizing the sine, cosine and tangent values of the typical angles (0, 30, 45, 60 and 90).

I hope this clears things up!
• USELESS if the video does not show how to answer this question with just calculations in the head. Give some shortcuts on how to solve SIN COS without a calculator. That would be useful
• The MCAT uses common angles, like 0, 30, 45, 60, 90. And those are easy to remember, I don't know why he used a ridiculous number. Plus, it you can recognize that it's a 3-4-5 triangle, you don't even need to do calculation! The MCAT sometimes doe that
• At first he said the angle is 36.8699 but later he said the angle is 36.899.
• It should have been 36.8699 (36.86989764584401...) or more accurately cos^-1(4/5).
• If a+b=c in the beginning, how does 3+4=5 make sense in the end of the video?
• Given that we are not allowed to use a calculator on the mcat exam, how can we do the calculation at without a calculator?
• The MCAT uses common angles, such as 0, 30, 45, 60, or 90. And those are easy to remember.
• Is there anyway you can slow down when you start putting the question and answers down you put them down to where I have to pause it just so I can keep up and also why did you not put the 6 in 36.899 because isn't supposed to be 36.8699?
(1 vote)
• If you go to the bottom right corner of the rectangle below the video and look for 'Options' (it is to the left of 'Share'), you can speed up or slow down playback. Best, Kim
(1 vote)
• why the "magnitude of our y component" not just "y component"?
(1 vote)
• When sal gave the angle of 36.8699 how did it then become 36.899? I think the time is did he just make an error?
(1 vote)
• At a clarification pops up addressing this. The angle originally should have been 36.899.
(1 vote)