Basic Kinematics - Initial Velocity

[Femme_physics]

Homework Statement

A truck drives in a straight line, east, from point A to point B, a distance of 180 meters, during 10 seconds, while slowing down at a constant rate of 6 meter per second squared.

Calculate the initial velocity.

The Attempt at a Solution

Attached. I don't think it's the correct answer, but according to the formula it should be!

 

[gneill]

Looks okay.

 

[Femme_physics]

Really? Because the solution manual tells me it's 21 m/sec. Did they make a mistake?

 

[gneill]

Who made the mistake depends upon whether the actual acceleration is 0.6m/s² or 6m/s².

 

[Femme_physics]

It's 0.6 m/s², for sure.

So THEY'VE made the mistake, right? Can you officially confirm that THEY'VE made the mistake, and not me?

 

[gneill]

It's 0.6 m/s², for sure.

So THEY'VE made the mistake, right? Can you officially confirm that THEY'VE made the mistake, and not me?

Officially, I'm here quite unofficially!

But in my opinion, if the problem statement say's that the acceleration is -6m/s², then their solution is incorrect.

 

[Femme_physics]

No no, the problem statement says that acceleration is -0.6 m/s². But, this is exactly what I plugged into the formula! So, now I'm confused, who's right here?

 

[gneill]

No no, the problem statement says that acceleration is -0.6 m/s². But, this is exactly what I plugged into the formula! So, now I'm confused, who's right here?

Your problem statement was:

A truck drives in a straight line, east, from point A to point B, a distance of 180 meters, during 10 seconds, while slowing down at a constant rate of 6 meter per second squared[/color].

and your solution image definitely shows a value of -6 being plugged in, the result for the (1/2)at² term being given as 300m.

 

[Femme_physics]

Ahhhhhhhhhhhhhhh'I'm stupid. *smacky foreheady*

:) Thanks.<- Idiot. Seriously.

Appreciate it.

<- Seriously.

-FP