# Average acceleration problem

## Homework Statement

The average speed of a nitrogen molecule in air is about 6.70 multiplied by 102 m/s, and its mass is about 4.68 multiplied by 10-26 kg.

(a) If it takes 1.80 multiplied by 10-13 s for a nitrogen molecule to hit a wall and rebound with the same speed but moving in an opposite direction (assumed to be the negative direction), what is the average acceleration of the molecule during this time interval?

(b) What average force does the molecule exert on the wall?

I have no idea

## The Attempt at a Solution

I dont even know how to attempt

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Delphi51
Homework Helper
We can't help much without seeing some effort from you.
It is accelerated motion. Have you any formulas for accelerated motion? Look for one with a change in velocity, Δv or Vf - Vi in it because you are given those values.

Obviously I've already exhausted all the resources I have and all the methods I've tried do not work or else I would not be here...the only formula I have with that is v^2-v_0^2=2a(x-x_0) but I dont have x...not sure what v and v_0 are either..

Delphi51
Homework Helper
There is a decent set of equations here: http://hyperphysics.phy-astr.gsu.edu/hbase/acons.html

Note that it uses V and Vo instead of Vf and Vi.
It says "acceleration is the slope on the velocity graph", which means a = Δv/Δt, a nice variation on the formulas it has with the V and Vo. Think of Δv as Vf - Vi. And Δt is just t if you are starting out at time zero.

There is a nice set of formulas and their derivations here:
http://en.wikiversity.org/wiki/Motion_-_Kinematics#Motion_with_constant_acceleration

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