# Motion in a straight line? [closed]

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?

-

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

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – John Rennie, akhmeteli, Qmechanic
If this question can be reworded to fit the rules in the help center, please edit the question.

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