What Does 92.5 m/s Represent in the Equation (V2-V1)^2?

[TheronSimon]

Homework Statement

(V2-V1)^2 = 552+452-2*55*45*cos135

= 92.5m/s



My question is how to get from the first equation to the answer...

 

[emailanmol]

552+452-2*55*45*cos135

Is not solved correctly.
It doesn't come up to 92.5(assuming the calculation you were working on didn't need change of units.

 

[TheronSimon]

its something from the course material, so i guess its just wrong...

 

[emailanmol]

Yeah, it sounds like wrong.
If you can perhaps add some back ground context we may be able to work out what the text wanted to convey :-)

 

[gneill]

Homework Statement

(V2-V1)^2 = 552+452-2*55*45*cos135

= 92.5m/s



My question is how to get from the first equation to the answer...

Looks suspiciously like an application of the cosine law where the exponents have lost their superscipt. Thus:

$x^2 = 55^2 + 45^2 - 2\cdot55\cdot45\cdot cos(135°)$

solve for x.

 

[TheronSimon]

haha! there we go thanks! i guess it it was just a typo in the course material.

 

[emailanmol]

OMG!
How did i miss that!
That was incredible observation gneill

 

[gneill]

OMG!
How did i miss that!
That was incredible observation gneill

I attribute it to to many hours doing math and not enough enjoying St. Patrick's day parties. I shall have to make amends

 

[jey1234]

OMG!
How did i miss that!
That was incredible observation gneill

I agree. Remarkable

 

[PeterO]

Homework Statement

(V2-V1)^2 = 552+452-2*55*45*cos135

= 92.5m/s



My question is how to get from the first equation to the answer...

What is supposed to be 92.5 m/s

V2, V1 or the difference V2 - V1 ?