# Homework Help: Quick acceleration word problem

1. Aug 9, 2008

### joe215

1. The problem statement, all variables and given/known data
An electron has an initial speed of 3.0 x10^5 m/s. It undergoes an acceleration of 8.0 x 10^14 m/s/s. (a) How long will it take to reach a speed of 5.4 x 10^5 m/s? (b) How far will it have traveled in this time?

2. Relevant equations

Rate x Time= Distance

3. The attempt at a solution

A. R x T= D

(8.0 x 10^14 m/s/s)(T)=(5.4 x 10^5 m/s)-(3.0 x10^5 m/s)

T= 3x10^18 seconds

B. How do you find the distance traveled? This is stumping me for some reason.

Thanks!!

2. Aug 9, 2008

### Astronuc

Staff Emeritus
Assuming the magnitude of acceleration is correct, that's a huge acceleration.

The T should be quite small.

What is the relationship between the change in velocity, acceleration and time?

3. Aug 9, 2008

### Redbelly98

Staff Emeritus
Joe has the correct relation, even if the terminology is a bit odd ("Distance" is really change in velocity, "Rate" is acceleration). He just needs to carefully redo the arithmetic given by that relation.

Part B: your textbook has 3 or 4 equations for motion with a constant acceleration. Look over them, and choose one which can be solved for distance using the given information.