Magnitude of average velocity and average speed

Homework Statement

An electron moves in the positive x-direction a distance of 2.44 m in 3.10 *10-8 s, bounces off a moving proton, and then moves in the opposite direction a distance of 1.68 m in 3.53*10-8 s.

The Attempt at a Solution

to find the average velocity I used the distance formula to find magnitude divide it by the c

Sqrt (2.44)^2+(1.68)^2 / (3.53*10^8 - 3.10*10^8) ?

for the average speed

(2.44 - 1.68) / (3.53*10^8 - 3.10*10^8)?

Can someone explain it by showing some work? I keep getting the wrong answer.

cepheid
Staff Emeritus
Gold Member
for the average speed

(2.44 - 1.68) / (3.53*10^8 - 3.10*10^8)?

Can someone explain it by showing some work? I keep getting the wrong answer.

This part is wrong for sure. The average speed would be the total distance travelled (without regard for direction) divided by the total time elapsed. The total time elapsed would be the SUM of the two time intervals, not the difference between them, right?

cepheid
Staff Emeritus