# Projectile Question Need help fast

1. Sep 22, 2009

### Peterr13

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

2. Relevant equations

3. The attempt at a solution

2. Sep 22, 2009

### rock.freak667

42??

3. Sep 22, 2009

### Peterr13

srry there is the question A pilot is required to fly directly from London, UK, to Rome, Italy in 3.5 h. The displacement is 1.4 x 10^3 hm [43 degrees E of S]. A wind is blowing with a velocity of 75 km/h [E]. Determine the required velocity of the plane relative to the air.

4. Sep 22, 2009

### rock.freak667

ok then, how fast should the plane fly if the wind was not blowing?

$$\vec{V_{P/A}}= \vec{V_P} - \vec{V_A}$$

5. Sep 22, 2009

### Peterr13

srry for the late reply im kinda new at this... it would be 1325?

6. Sep 22, 2009

### rock.freak667

I don't think that is the answer.

If the plane must travel 1.4x103 km in 3.5h , how fast should it travel? (this is vp)

When you get this vp acts 43 degrees E of S, so on your vector diagram draw this and vA=75 km/h E.

Last edited: Sep 22, 2009
7. Sep 22, 2009

### Peterr13

^
|43
|
|
1400 |________> looks right?

8. Sep 22, 2009

### Peterr13

^
|
|
|
|________> looks right? the left side is 1400 km, top left is 43 degrees, bottom is 75

9. Sep 22, 2009

### Peterr13

o wait is the hypotnuse 1400 instead?

10. Sep 22, 2009

### rock.freak667

Code (Text):
------------
\ 43
\
\
\
should be like this 43 degrees south of east.

Draw the velocity of air now. And then find

$$\vec{v_{P/A}} = \vec{v_P} - \vec{v_A} =\vec{v_P} + (- \vec{v_A})$$

EDIT: you need to find vP and draw this on the diagram with the air. You can't have a vector diagram adding different types of vectors

11. Sep 22, 2009

### Peterr13

1325

12. Sep 22, 2009

### rock.freak667

what units are that in? Put vP in km/h

13. Sep 22, 2009

### Peterr13

ok 1325 km/h

14. Sep 22, 2009

### Peterr13

wat does the time have to do with this question now?
to find distance?

15. Sep 22, 2009

### Peterr13

o kk so is the displacement 400 km/h.... in the beginning i was reading the question wrong i thought it was 1400km/h

16. Sep 22, 2009

### rock.freak667

the velocity is 400 km/h