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## Homework Statement

This is not a homework question, but rather a review question. I have the answer, ill post below, but have no idea how to get to the answer :)

Question: "A constant force of 90.0N acts on a ball while it has a displacement of 1.40m at 10 degrees below the x-axis. The force makes and angle of 60 degrees with the x-axis, as shown in the figire (DO you guys need the figure to figure this out?)

A) Express the force, F, and the desplacement d, in unit vector notation?

The correct answer is:

F=(45 N i) + (77.9 N j)

d = (1.38 m)i - (0.243 m)j

Can anyone help me out on how to figure this out please?

THanks!

## Homework Equations

## The Attempt at a Solution

For F - Do I just go 90cos(60) = 45.0 N ? (Can you explain to me why I use COS for that one?

I guess what I am having trouble with is knowing which is i (sin or cos) and which is j (sin or cos)

?

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