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I am trying to solve the following problem that involves motion in a straight line. I am not quite sure how to go about it though. I know it will involve formulas and derivatives but which specific ones would I use?

An electron has a constant acceleration of 2.6 m/s^2. At a certain instant its velocity is 12.1 m/s.

What was its velocity 2.5 s earlier? What was its velocity 2.5 s later?

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closed as off-topic by John Rennie, akhmeteli, Qmechanic Sep 23 '13 at 20:45

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For constant acceleration, $\Delta v = a \Delta t$. – Alfred Centauri Sep 23 '13 at 17:27

Unless the particle being an electron is a catch, standard equations of motion can be used. $v= u + at$ with symbols having usual meanings. for 2.5 sec earlier: $v = 12.1 \mathrm{\ m/s}$, $a = 2.6 \mathrm{\ m/s^2}$, $u = ?$, $t = 2.5 \mathrm{\ s}$

Similarly for 2.5 sec later $v = ?$, $a = 2.6 \mathrm{\ m/s}^2$, $u = 12.1\mathrm{\ m/s}$, $t = 2.5 \mathrm{\ s}$.

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