Unit Vector Notation: Solve a1, a2 for Vector Equation

AI Thread Summary
The discussion focuses on solving for vectors a1 and a2 in the equations involving vector a3, which is defined as 2i + 2j. By substituting a3 into both equations, the user attempts to express a1 and a2 in unit vector notation. Initial attempts yield values for a1 and a2 that satisfy one equation but not the other, indicating a need for a systematic approach. The key is to treat the two equations as a system of linear equations to find consistent values for a1 and a2. Ultimately, solving these equations will provide the correct expressions for both vectors in unit vector notation.
saber1357
Messages
67
Reaction score
1

Homework Statement



Vector a1 + vector a2 = 5*vector a3
Vector a1 - vector a2 = 3*vector a3
Vector a3 = 2i + 2j (i and j are the vector components)
Express 1) vector a1 and 2) vector a2 in unit vector notation

Homework Equations


Vector R = Ax + Yx

The Attempt at a Solution


I took the first equation and replaces the a3 with 2i+2j, so vector a1 + vector a2 = 5(2i + 2j)
a1 + a2 = 10i + 10j
I solved for R and found direction, but I do'nt believe that helps at all. (R = sqr root of 200 and direction was 45 degrees).
From the first equation with addition, I could conclude that vector a1 could equal = 10i +0j and vector a2 could equal 0i + 10j. However, these values don't work for the second equation with the subtraction. Is there some sort of secret to this problem?
 
Last edited:
Physics news on Phys.org
Don't worry about magnitudes and angles for this problem. This one is straight algebra. substitute a3 into the second equation also. That'll give you another equation with a1 and a2.

You have two equations with two unknowns (a1 and a2)... solve those, get a1 and a2.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top