What are the x- and y-components of the velocity vector?

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SUMMARY

The discussion focuses on calculating the x- and y-components of a velocity vector represented in a physics problem. The user initially attempted to use the formulas -100 m/s*cos(30 degrees) for the x-component and -100 m/s*sin(30 degrees) for the y-component but received incorrect results. The correct approach involves using cosine for the y-component and sine for the x-component, as clarified by a forum member. This adjustment is crucial for accurately determining the components of the vector.

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jamal.kun
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Homework Statement


Question is: What are the x- and y-components of the velocity vector shown in the figure?
knight_Figure_03_22.jpg


https://session.masteringphysics.com/problemAsset/1384003/6/knight_Figure_03_22.jpg

The Attempt at a Solution


I tried -100 m/s*cos(30 degrees)=-86.6m/s for the x component and -100m/s*sin(30 degrees)=-50m/s for the y component, but was incorrect for both. What am I missing?
 
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jamal.kun said:

Homework Statement


Question is: What are the x- and y-components of the velocity vector shown in the figure?
knight_Figure_03_22.jpg


https://session.masteringphysics.com/problemAsset/1384003/6/knight_Figure_03_22.jpg

The Attempt at a Solution


I tried -100 m/s*cos(30 degrees)=-86.6m/s for the x component and -100m/s*sin(30 degrees)=-50m/s for the y component, but was incorrect for both. What am I missing?

Welcome to the PF.

You got the sin & cos backwards. Try drawing the line from the tip of the vector to the negative y axis. See how the component of the vector on the negative y-axis involves the cos(30 degrees)?
 
Thanks berkeman, I see what you mean now. I didn't expect something like that. Thank you for the incredibly quick reply.
 
If we drawing the line from the tip of the vertor to the negative y-axis then What will be its angle with x axis and negative y-axis?
 
Abdullah Wali said:
If we drawing the line from the tip of the vertor to the negative y-axis then What will be its angle with x axis and negative y-axis?
If you are asking jamal.kun, the thread is seven years old and jamal is no longer a forum member.
 

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