- #1

Catchingupquickly

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## Homework Statement

An ice hockey puck leaves a hockey stick with a velocity of 45 m/s, how far will it travel in 3.0 seconds?

## Homework Equations

D = v/t or

## \Delta \vec d= \frac 1 2 \vec a \Delta t^2##

with ## \vec a = v_2 / \Delta t##

## The Attempt at a Solution

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D = v/t

= 45 m/s / 3 = 135 meters

or ##0.5 (15 m/s^2) (3)^2## = 67.5 meters

Which one is it, and more importantly... how do I tell the difference on when to use each formula?

Thank you