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The question then asks me to write an expression for the ball’s velocity, v, using unit vectors for the x-direction and the y-direction. Wouldn’t the velocity be just 5.4m/s? I don’t understand wht they are asking.

- Thread starter UrbanXrisis
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- #1

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The question then asks me to write an expression for the ball’s velocity, v, using unit vectors for the x-direction and the y-direction. Wouldn’t the velocity be just 5.4m/s? I don’t understand wht they are asking.

- #2

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In this case: the x-component of the speed is just 5.4cos(30), so that part of the vector is (5.4cos(30))*ex (actually make that x subscript and add an arrow above the e)

The y-component is thesame thing, only with 5.4sin(30) and ey. In case they ask you to do the expression for t, you'll have to add acceleration like this:

V = (5.4cos(30))*ex + (5.4sin(30) + ..acceleration*t..)*ey

This describes the vector.

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- #4

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Just sketch an arrow making 30 degrees with the horizontal. Then project the vector onto the x-axis and that's your x-component. It's that easy.

Magnitude of the vector in the x-direction is as you described, 5.4cos30. The direction of motion with respect to the x-axis will be 30 degrees.

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