(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The position of a 5kg particle moving in the x-y plane varies as a function of time according to the expression

r = [(3t + 1)m]i + [(-4t^2 +5t + 2)m]j

(r is a vector I just didn't know how to make the arrow over head)

Find the kinetic energy of the particle as a function of time

2. Relevant equations

k = 1/2 mx+b

3. The attempt at a solution

d/dx r = [(3t + 1)m]i + [(-4t^2 +5t + 2)m]j

v = 3i + (-8t +5)j

v =(3i^2 + (-8t +5)j^2)^(1/2)?????????????

......................................

3t+1 = 0

t= 1/3 for x

-4t^2 +5t + 2

t= -.44 or t= 1.69 for y????????????

Very confused don't know what vector r is. Is it already a function of time or what. I'm very confused and don't understand how to solve please help

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# Homework Help: How to find kinetic energy of a particle as a function of time?

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