Another vector question

[oriont]

The problem reads: "A car is traveling at a speed of 50km/hr. The positive y-axis is north and the positive x-axis is east. Resolve the car's velocity vector into two components if the car is traveling in each of the following directions"

I Get:

A)East = 50i
B) South= -50j

However where I get into problems is when it comes to
C) Southeast (The book states 25 square-root (2) i,- 25 square-root (2) j)
D) Northwest (The book states -25 square-root (2) i, 25 square-root (2) j)

Not sure how they arrived at the answers for C and D

 

[tkhunny]

You should memorize a few commonly used angles, usually 0º, 30º, 45º, 60º, 90º. You need 45º for this one.

It's important to note that a 45-45-90 right triangle is also an isosceles triangle.

 

[oriont]

You should memorize a few commonly used angles, usually 0º, 30º, 45º, 60º, 90º. You need 45º for this one.

It's important to note that a 45-45-90 right triangle is also an isosceles triangle.

I see, such that 45º =square-root (2)/2

 

[tkhunny]

Well, equality is not the right designation, but that is the relationship of the legs and the hypotenuse of such a triangle.