Sunday
March 29, 2015

Homework Help: Physics

Posted by Physics on Friday, September 18, 2009 at 9:18pm.

I gues I'm looking at this the wrong way i do not understand the work you do to get to the answer

Question:

Find the air velocity of a plane that must have a realtive ground velocity of 250.0 h^-1 km norht if it encounters a wind pushing it toward the northeast at 75 h^-1 km

The Work:

I do not follow it one bit...

Va = Vg - Vw
= 250 h^-1 km north - 75.0 h^-1 km northeast
= 250.0 h^-1 km north + 75.0 h^-1 km southwest
Va^2 = Vg^2 + Vw^2 - 2VgVw cos A
= (250.0 h^-1 km)^2 + (75.0 h^-1 km)^2 - 2(250.0 h^-1 km)(75.0 h^-1 km)(cos 45.0)
= 62 500 h^-2 km^2 + 5 625 h^-2 km^2 + 26 516 h^-2 km62
= 41 609 h^-2 km^2
Va = 204 h^-1 km
Vw/sin W = Va sin A
sin W = Vw sin A/Va
= (75 h^-1 km)(sin 45.0)/(204 h^-1 km)
= (75 h^-1 km)(.707)/(204 h^-1 km)
= 0.260
B = 15.1
Answer = 204 h^-1 km, 15.1 degrees west of north

ok i was lost on line 2 and three were the added and subtracted 75 with two different directions why are there two

line 3 were did this come from

- 2VgVw cos A

thanks!

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

physics - find the air velocity of a plane that must have a relative ground ...
Physics - A pilot must fly his plane to a town which is 200km from his starting ...
Physics - The pilot of a plane measures an air velocity of 186 km/h south. An ...
Physics - A pilot must fly his plane to a town which is 200 km from his starting...
Physics (please help!!!!) - A skydiver is subject to two forces: gravity and air...
Gr. 12 Physics - A pilot must fly his plane to a town which is 200km from his ...
Physics - 1. A small plane can travel at 200 km/h in still air. If a 50.0 km/h ...
Physics - A plane is headed due west with an air speed of 221 m/s. The wind ...
Physics - 1)The velocity of sound in air is 332 m/s. If the unit of length is km...
Physics - I'd like to know when it is appropriate to use each formula. Im new to...

Members