# Homework Help: Problems for Understanding

1. Sep 16, 2009

### FlipMC

1. The problem statement, all variables and given/known data

A cyclist is traveling with an average velocity of 5.9 m/s[W]. What will be his displacement after 1.2 h?

2. Relevant equations

d = v1▲t+½a▲t^2 ?

3. The attempt at a solution

Vavg = 5.9 m/s
▲t = 1.2 x 60 = 72 m/s

What I did was use d = v x t and I got 424m/s, which is 1, 526.4 km/h. But that's way off from my the textbook's answer which is, 26km[W]..

It sounds so easy but honestly, I'm going crazy trying to figure it out LOL .

2. Sep 16, 2009

### rl.bhat

Cyclist is traveling with uniform velocity.
So the displacement = velocity*time.
Convert 1.2 hours to seconds

3. Sep 16, 2009

### Kalvarin

You gotta get everything in the same units. We have velocity in m/s so we want time in seconds.

1.2 hours = 72 minutes = 4320 seconds

Then just use:

Distance = Velocity*Time

4. Sep 16, 2009

### FlipMC

Thanks guys.
So I did D = 5.9m/s x 4320 which equaled to 25, 488m/s?
Then, to change it back to km/h, times 3.6 then it equaled 91, 756.8?!
What am I doing wrong? :(

5. Sep 16, 2009

### rl.bhat

In the problem displacement is asked, not the velocity.

6. Sep 17, 2009

### FlipMC

Hm, right.. AMG, I still don't get this :'(