# Calculating Velocity (It easy, I just dont listen)

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How in the world do I do this?

I know it's easy, I just didnt listen, and as a result have no clue what to do:

Some dudes cycle. They travel 6 km North, 4 km East, 6 km South, 4 km East, 3 km north.

If the ride took them 10 minutes, what is their average velocity?

Thanks...sorry about me being a retarded monkey.
"Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, your eyes will get sore after a while."
13.8 km/hr
Quote by Gutch220
13.8 km/hr

Isn't that just their average speed? Or am I confused?
"Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, your eyes will get sore after a while."
Work out where he moved to relative from his start point.

Work out the distance between start point and end point (a direct distance, not going round all the roads etc.)

Divide by time taken.

Distance should be in metres and time in seconds.
Co-President of UG's Tubgirl Virgins Club

velocity = mass x acceleration
curses! foiled again

Epiphone Les Paul Custom "Silverburst"
ok, 13.8 km/hr north

velocity is just speed with a direction
velocity = displacement / time.

He travels a total of 9km north, 6km South and 8km East.

That's the same as travelling 3km North and 8km East.

Using Pythagoras' theorem:

Displacement = √(9 + 64) = √73

Velocity = √73 / 600 * 1000 (600 seconds in 10 minutes, 1000 metres in a kilometre)
Populus vult decipi. Decipiatur.

Quote by Mistress_Ibanez
It's can be a contraction and genitive case.

Quote by Mistress_Ibanez
If you cut down on these costs students won't learn so well, effecting the "quality"...
Quote by JamieB
Work out where he moved to relative from his start point.

Work out the distance between start point and end point (a direct distance, not going round all the roads etc.)

Divide by time taken.

Distance should be in metres and time in seconds.

You mean his displacement? It's 8.5 km.

8500m/600s

is 14.1 m/s?
"Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, your eyes will get sore after a while."
I think I get the same as Frenchy

Co-President of UG's Tubgirl Virgins Club

im not 100% sure, but since its 'velocity' i think you would need to resolve into components and find the angle of the resultant (or maybe im being silly and its much simpler)
Crap, you guys just confused me way more.
"Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, your eyes will get sore after a while."
Okay, you understand the difference between velocity and speed, right?

That pretty much sums it up.

He goes north 6 kilometres and then south 6 kilometres (ignore the 4km east in the middle).

These cancel out. After that, he goes back north 3km. So he's now 3km north of his starting point.

He travelled west 0km and east 8km, so he's not just 3km north, he's also 8km east from his start point. Helping?

You now need to know how far his finishing point is from his start point. To do this, we use Pythagoras' theorem of right angled triangles. This works out his displacement.

10 mins = 600 seconds

1000m in 1km, so you multiply route73 by 1000 to get it in metres. Then divide by 600. This puts in in metres per second, the SI unit for velocity.
Co-President of UG's Tubgirl Virgins Club

Last edited by JamieB at Jan 22, 2007,
Quote by JamesDouglas
How in the world do I do this?

I know it's easy, I just didnt listen, and as a result have no clue what to do:

Some dudes cycle. They travel 6 km North, 4 km East, 6 km South, 4 km East, 3 km north.

If the ride took them 10 minutes, what is their average velocity?

Thanks...sorry about me being a retarded monkey.

Displacement does not matter here at all.

v = s / t

t=600 secs

s = 6 + 4 + 6 + 4 + 3 = 23 km = 2300 m

v = 2300 m / 600 s = 23/6 m/s

There...almost 4 m/s

edit : lol forgot it's velocity ... that makes vectors come in to the equation disregard my post
Quote by Hotpunksk8rgirl
EWWWWW!!!!! Isn't a urethra another word for a female body part(vagina)??????? Perverted fishy.
^Wrong.

Velocity and speed are two different things.

Velocity = DISPLACEMENT / time
Speed = DISTANCE / time
Populus vult decipi. Decipiatur.

Quote by Mistress_Ibanez
It's can be a contraction and genitive case.

Quote by Mistress_Ibanez
If you cut down on these costs students won't learn so well, effecting the "quality"...
if it helps:
speed= scalar quantity so only magnitude (i.e. 10m/s) but no direction
velocity= vector quantity so both magnitude and direction (i.e. 10m/s at 090° bearing)
Bronek for the loss
Co-President of UG's Tubgirl Virgins Club

do you know how to resolve forces into components? which subject is this like physics or math mechanics?
This isn't about putting forces into components. It's just a simple displacement/time equation.
Co-President of UG's Tubgirl Virgins Club

Quote by JamieB
Bronek for the loss

Nuh-uh ... i realized it so I edited

Quote by FrenchyFungus
^Wrong.

Velocity and speed are two different things.

Velocity = DISPLACEMENT / time
Speed = DISTANCE / time

Quote by Hotpunksk8rgirl
EWWWWW!!!!! Isn't a urethra another word for a female body part(vagina)??????? Perverted fishy.
Jamie you nerd, it's not 'ms^-1' it's m/s. Stop showing off
Quote by chubbychunks
Jamie you nerd, it's not 'ms^-1' it's m/s. Stop showing off

sorry tubby

I mean, chubby
Co-President of UG's Tubgirl Virgins Club

You know what? I'm not going to do it. There, I said it. So there.
"Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, your eyes will get sore after a while."
Dude, we just showed you step by step how to do it

Have you tried Google? Maybe it can explain better.
Co-President of UG's Tubgirl Virgins Club

well if it was components then frenchyfungus is right and the bearing of the resultant force would be 90° - (tan^-1(3/8))

Frenchy just did a displacement/time equation, like was needed

Co-President of UG's Tubgirl Virgins Club

It's ok guys, I gave up.
"Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, your eyes will get sore after a while."
he didnt actually (or atleast that's what i think)....or maybe im just overcomplicating things heck when they say velocity they probably just mean speed; at earlier levels the two terms are frequently swapped around....my bad i guess
NO!

No you didn't.

Right;

You know the difference between velocity and speed, right?

EDIT: No, it's referring to velocity, it's just a matter of working out the displacement and dividing it by the time. Nothing more
Co-President of UG's Tubgirl Virgins Club

velocity is a vector so 'technically' it would need a direction....
Quote by JamieB
NO!

No you didn't.

Right;

You know the difference between velocity and speed, right?

EDIT: No, it's referring to velocity, it's just a matter of working out the displacement and dividing it by the time. Nothing more

How about you just give me the answer and I say thanks?
"Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, your eyes will get sore after a while."

As in the square root of 73 (somewhere between 8 and 9) multiplied by 1000 then divided by 600.

I don't think he's studying for a degree, classical gas, it doesn't need to get that technical.

Okay, route 73 is somewhere between 8.5 and 8.55 (can't find a square root button on MS calculator), so you can put that to 8.5 to 2 significant figures.

Times by 1000 = 8500

8500/600

= 14.2ms^-1 (3sf)
Co-President of UG's Tubgirl Virgins Club

Last edited by JamieB at Jan 22, 2007,
Quote by JamesDouglas
How about you just give me the answer and I say thanks?

14.24 m/s
Populus vult decipi. Decipiatur.

Quote by Mistress_Ibanez
It's can be a contraction and genitive case.

Quote by Mistress_Ibanez
If you cut down on these costs students won't learn so well, effecting the "quality"...
Quote by FrenchyFungus
14.24 m/s

Thanks.
"Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, your eyes will get sore after a while."
Quote by JamieB
sorry tubby

I mean, chubby

And I suppose you do m/s/s as ms^-2?
yea i guess so JamieB, sorry i just had an A level mechanics exam, so you know, my head is still into 'math mode'
Quote by JamesDouglas
Thanks.

You won't learn that way!
yeah, I know what you mean. You just gotta know when to go back to basics

And yes, I do put ms^-2. When you get to A-level, you have to. Just as you have to put distance/m when labelling axes, not distance (m).
Co-President of UG's Tubgirl Virgins Club

It's velocity, so you need to say the direction as well. You'll lose marks for it if you don't.
Quote by Robbie n strat
It's velocity, so you need to say the direction as well. You'll lose marks for it if you don't.

well atleast someone agrees