The particle has 
and 
, and is undergoing a constant acceleration of 
.
This means its position at time 
is given by the vector function,
![\implies\vec r(t)=\left[4\,\mathrm m+\left(2\dfrac{\rm m}{\rm s}\right)t-\left(1\dfrac{\rm m}{\mathrm s^2}\right)t^2\right]\,\vec\imath-\left(1\dfrac{\rm m}{\mathrm s^2}\right)t^2\,\vec\jmath](https://tex.z-dn.net/?f=%5Cimplies%5Cvec%20r%28t%29%3D%5Cleft%5B4%5C%2C%5Cmathrm%20m%2B%5Cleft%282%5Cdfrac%7B%5Crm%20m%7D%7B%5Crm%20s%7D%5Cright%29t-%5Cleft%281%5Cdfrac%7B%5Crm%20m%7D%7B%5Cmathrm%20s%5E2%7D%5Cright%29t%5E2%5Cright%5D%5C%2C%5Cvec%5Cimath-%5Cleft%281%5Cdfrac%7B%5Crm%20m%7D%7B%5Cmathrm%20s%5E2%7D%5Cright%29t%5E2%5C%2C%5Cvec%5Cjmath)
The particle crosses the x-axis when the 
component is 0 for some time 
, so we solve:
The negative square root introduces a negative solution that we throw out, leaving us with 
or about 3.24 seconds after it starts moving.
Answer:
Explanation:
A mover carries a box across a room. A weightlifter lifts a barbell off the ground. A weightlifter holds a barbell above the head.
that what i think
I believe the correct answer from the choices listed above is the first option. <span>A blimp flying around over the Super Bowl has both kinetic and potential energy. It initially posses potential energy then as it moves te said energy is converted to kinetic energy. Hope this answers the question.
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