please solve the attached problem

Asked by ayushmishradbb | 11th Jun, 2020, 09:07: AM

Expert Answer:

Two forces 
F1  = (i + j + k) N 
F2 = (i + 2j + 3k) N 
 
r1 = (2i + 3j + 4k) m 
r2 = (5i + 4j + 3k) m
 
N e t space f o r c e comma space F space equals space F 1 space plus space F 2 space equals space 2 i with hat on top space plus space 3 j with hat on top space plus thin space 4 stack k space with hat on top
P o s i t i o n space v e c t o r space b e t w e e n space t w o space p o i n t s space
r with rightwards arrow on top space equals space left parenthesis 5 minus 2 right parenthesis i with hat on top space plus space left parenthesis 4 minus 3 right parenthesis j with hat on top space plus space left parenthesis 3 minus 4 right parenthesis space stack k space with hat on top
r space equals space 3 i with hat on top plus j with hat on top minus stack k space with hat on top
W o r k space d o n e space
W space space equals space F. r space
W space space equals open parentheses space 2 i with hat on top space plus space 3 j with hat on top space plus thin space 4 stack k space with hat on top space close parentheses. left parenthesis 3 i with hat on top space plus j with hat on top space minus space stack k space with hat on top right parenthesis space
W space space equals space 2.3 space plus space 3.1 space minus space 4.1 space equals space 6 space plus space 3 space minus 4 space space equals space 9 space minus space 4 space space equals 5 space J space 
 
Option (A) - correct

Answered by Shiwani Sawant | 12th Jun, 2020, 04:06: PM