Engineering Mechanics - Force Vectors - Discussion

Can someone show me how to find α and β for F2?

I got the same problem whenever the only angle on the x-y plane is given, not directly from x and y-axis. Thank you in advance!

Thanks @Manoj.

f = xi + yj + zk.

x is x component of force
y is y component of force
z is z component of force

By Considering the direction of the force
It is making 60 deg with positive y-axis and negative x-axis. and 45 deg with positive z-axis.
Cos theta(x) = x component of force/ magnitude of x.

Therefore x component = -(cos 60*400) = 200 since it is in negative direction
Similarly y component = cos 60 * 400 = 200.
z component = cos 45 * 400 = 283.
Therefore force in cartesian form is -200i+200j+283k.

Please give the complete solution of this question.

Please give me the complete solution of this question.

The answer is right. Take it as cos60 along the y-axis.

Answer for this question should be A because cos120=-1/2 along with y-axis.

Please give me reply.