A Jet Airplane Problem...

[Mysterix]

Here's another one:

N, S, E, W, stands for North, South, East, and West.

A Boeing 777 is flying at 720 km/h [N 25 degrees E] and then executes a turn that brings it to a new velocity of 770 km/h [S 50 degrees E]. The turn took 10.0s. Determine the acceleration. Answer in m/s^2.

Anyone? Thanks...

[mykg4orce1]

speaking of components... can't this problem be done that way???

[prog_tom]

Linear Acceleration:

a = vv/vt;

a = 1.4 m/s^2

[prog_tom]

Rotational Acceleration,

If not mistaken, it's

-4.3m/s^2

[mykg4orce1]

prog_tom i dont know what u did....maybe cause im tryig to use high school physics.

Anyway I am nt guru at this and I may have this completey wrong, this is what i did:





Can anyone confirm this????

[mykg4orce1]

please ??

[silva]

I don't think so.

You have: c = 1182.5 kmh^-1 then you convert it to ms^-1.

You say that it is 328.47 m/s

But to convert to m/s wouldn't it be: 1182.5 / 1000 (-> meters / hour) then * 3600 (-> meters / second), giving 4257 ms^-1?

I'm not sure, but I think the answer is 288 ms^-2.

Acceleration = delta v (displaced distance) / delta t (displaced time)

So, 2592 cos 65 + 2772 sin 40 = 1095 + 1782 (approx.) = 2877

2877 / 10 = 288 ms^-2

Of course you could do it with greater accuracy and I am not 100% sure - we just started doing vectors today.

Let me know how it goes.

s.

[sql_lall]

Just interested why you figured out v2 - v1, instead of v2+v1

Surely the question is just asking you to find the average acceleration (otherwise it would be like.."Graph the acceleration")

Now, i'm not sure exactly, but it seems some stuff like this may be useful:
a) Total time = Time taken to fly 1st bit + 10 sec + Time taken to fly 2nd bit
b) Total Displacement (or DISTANCE, if the acceleration wanted is not a vector, but it seems to be) = Displacement for 1st bit + Displacement for 2nd bit (=v1 + v2)

[silva]

Hey, you talking to me?

It's asking for the acceleration throughout the turn.

We did a similar problem for school but I've handed it in...

s.

[sql_lall]

Nah silva. Soz, i was just looking at the picture by mykg4orce1, how he had v2-v1. I was just intrigued.

Oh, and what is the difference between turning acceleration and normal acceleration? Cos we haven't done that yet in fizix, only normal acceleration in 1 direction
(*so* boring so far, it's like '"and everyone, this is a vector...")
So yeah, is it just something like the triangles mykg4orce1 set up?

[silva]

122.65 ms^-2

i think

i'll post tonight

s.

[silva]

Where's this question from?

Anyway, using vectors, components etc:

x_final = 770 sin 50
y_final = -770 cos 50

x_initial = 720 sin 25
y_initial = 770 cos 25

/\x = (770 sin 50 - 720 sin 25)
/\y = (770 cos 25 + 770 cos 50)

Äv = root(/\x² + /\y²)

a = /\v / /\t

/\t = 10s

/\v = 1226.511ms^-1

.'. a = 122.65ms^-2

I think that's right.

Let me know how it goes.

s.

[prog_tom]

Originally posted by silva
Where's this question from?

Anyway, using vectors, components etc:

x_final = 770 sin 50
y_final = -770 cos 50

x_initial = 720 sin 25
y_initial = 770 cos 25

/\x = (770 sin 50 - 720 sin 25)
/\y = (770 cos 25 + 770 cos 50)

Äv = root(/\x² + /\y²)

a = /\v / /\t

/\t = 10s

/\v = 1226.511ms^-1

.'. a = 122.65ms^-2

I think that's right.

Let me know how it goes.

s.

so, according to your answer, after 10 seconds, the velocity would be 1227 m/s + 720km/h, or 1227 m/s + 200m/s, which would be 1427m/s????

[prog_tom]

Originally posted by sql_lall
Nah silva. Soz, i was just looking at the picture by mykg4orce1, how he had v2-v1. I was just intrigued.

Oh, and what is the difference between turning acceleration and normal acceleration? Cos we haven't done that yet in fizix, only normal acceleration in 1 direction
(*so* boring so far, it's like '"and everyone, this is a vector...")
So yeah, is it just something like the triangles mykg4orce1 set up?

Rotational Acceleration is a little different from Linear Acceleration:

Rotational accel = change in rotational velocity / time

rotational velocity = 2pi * frequency = angle travelled /time

[prog_tom]

Originally posted by silva

Acceleration = delta v (displaced distance) / delta t (displaced time)

Isn't it suppose to be change in VeLOCITY? Can you do Algebra 1?