Physics Vectors Help!!! Am I supposed to somehow use the Pythagorean theorem to answer this? I've tried multiple times to answer, but what is the best way to solve this sort of problem???

enter image source here

2 Answers
Jan 18, 2018

Consider that,

#vec M# is the sum of #vec P# and #vec Q#. Moreover, consider that,

#vec P# and #vec Q# have been resolved into their components in the question. With this data, we may find the magnitude via,

#V = sqrt(V_x^2+V_y^2)#

Thus,

#abs(P) = sqrt(21^2+6^2) approx 21cm#, and

#abs(Q) = sqrt(25^2+9^2) approx 27cm#

Recall that #vec M# is the sum of the preceding vectors,

#M_x = P_x+Q_x = 4cm#, and
#M_y = P_x+Q_x = 15cm#

Therefore, the magnitude of the resultant vector #vec M# is,

#abs(M) = sqrt(4^2+15^2) approx 16cm#

Hence, I would wager that,

puu.sh

is a fairly accurate sketch of the vectors, color coded per the question's specifications.

I'm open to feedback if I made a mistake!

Jan 18, 2018

#"please review the details below."#

Explanation:

  • The P vector and its components are shown on the drawing.

enter image source here

  • You can find the magnitude of the P vector with the Pythagorean theorem.

#P=sqrt((-21)^2+6^2)=sqrt(441+36)=21.84" cm"#

  • The Q vector and its components are shown on the drawing.

enter image source here

  • Magnitude of Q Vector :

#P=sqrt((25)^2+9^2)=sqrt(625+81)=26.57 " cm"#

  • View of the P and Q vectors.

enter image source here

  • Let's draw the vector M = P + Q.

#vec M_x=vec P_x+vec Q_x=-21+25=+4" cm"#

#vec M_y=vec P_y+vec Q_y=+6+9=+15" cm"#

enter image source here

  • The magnitude of M=P+Q:

#M=sqrt(4^2+15^2)=sqrt(16+225)=sqrt(241)=15.52 " cm"#