- #1

physics604

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**1. The displacement (in meters) of a particle moving in a straight line is given by the equation of motion s=[itex]\frac{1}{t^2}[/itex], where**

*t*is measured in seconds. Find the velocity of the particle at times t=a, t=1, t=2, and t=3.## Homework Equations

v=[itex]\frac{d}{t}[/itex]

## The Attempt at a Solution

The question says the d=[itex]\frac{1}{t^2}[/itex]

I plug that into V=[itex]\frac{d}{t}[/itex], getting s=[itex]\frac{1}{t^3}[/itex].

When I input t=a, 1, 2, and 3, I get [itex]\frac{1}{a^3}[/itex], 1, [itex]\frac{1}{8}[/itex], and [itex]\frac{1}{27}[/itex].

However, the textbook says that the answers are -[itex]\frac{2}{a^3}[/itex], -2, -[itex]\frac{1}{4}[/itex], and -[itex]\frac{2}{27}[/itex].

Where did it get the -2 from? What am I doing wrong?

Thanks in advance.