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Help with Physics Question

Having a basic and fundamental knowledge of Physics, I was able to solve the Following question:

Town A lies 20 km North of town B. Town C lies 13 km West of town A. A small plane flies directly from town B to C. What is the Displacement of the Plane?

a) 33 km [W 33degrees N]
b) 19 km [W 33degrees N]
c) 24 km [W 57degrees N]
d) 31 km [W 57degrees N]
e)6.6 km [W 40degrees N]


My answer was a).

I got my answer by adding 20 and 13. Is this correct?
 

Answers and Replies

248
0
HI mercifulboss, actually the answer is C)24 Km.

Try drawing a simple overview of the situation:

plane.jpg

The question is trying to simply test your knowledge of the pathagareom theorem.
the path that the plane travels from B to C is the Hyperbole of a triangle made by A, B, and C. If you simple us the equation: A^2 + B^2 = C^2
you get: C^2 = 579 km.
So then: C = 24 km.
 
HI mercifulboss, actually the answer is C)24 Km.

Try drawing a simple overview of the situation:

View attachment 13530

The question is trying to simply test your knowledge of the pathagareom theorem.
the path that the plane travels from B to C is the Hyperbole of a triangle made by A, B, and C. If you simple us the equation: A^2 + B^2 = C^2
you get: C^2 = 579 km.
So then: C = 24 km.

Thank you.

But when do you add up 20 and 13? In what situations?
 
248
0
Well as far as trigonometry goes you wouldn't really ever need to do that. There isn't a certain formula that requires that operation. However it does depend on the situation and there could be a million different possibilities for needing to add those, just not this one :cool:
 
if the question had stated that the plane went from b to a to c and asked for the distance traveled you would answer 33, but since it asked for displacement path traveled does not matter, only the straight distance from c to b
 
5
0
so we need x

therefore X=20(j) + 13(-i)
______________
lXl=/ (20)^2+(13)^2
_____
=/ 569
= 23.88~24km
 

Attachments

malawi_glenn
Science Advisor
Homework Helper
4,782
22
Vishal60: Never post full solution!!!

Read and follow the rules.
 

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