Question

A vector of magnitude 20 is added to a vector of magnitude 25. The magnitude of this sum
might be:
A. zero
B. 3
C. 12
D. 47
E. 50
ans: C

why 12?

Answer 1

@RadEn help pls...

Answer 2

well. i just think easier about an inequality triangle :
let given a triangle with all sides 12,20,25
checking : 12+20 > 25 (right)
12+25 > 20 (right)
20+25 > 12 (right)
so, 12 is the rest side which satisfies for a triangle

Answer 3

just verify, why options A, B,D, and E are wrong :
because : 0+20 > 25 (wrong)
3+20 > 25 (wrong)
20+25 > 47 (wrong)
20+25 > 50 (wrong)
that's why, 12 is correct option only....

Answer 4

thanks @RadEn
another question?:
A vector has a magnitude of 12. When its tail is at the origin it lies between the positive x
axis and the negative y axis and makes an angle of 30
◦
with the x axis. Its y component is:
A. 6/√3
B. −6√3
C. 6
D. −6
E. 12
ans: D
i tried to solve it and what i got for y is letter B..but not real sure