A particle moves from a point (–2î + 5ĵ) to (4ĵ + 3k̂) when a force of (4î + 3ĵ) N is applied. How much work has been done by the force?
2 J
8 J
11 J
5 J
Explanation:
$\overrightarrow{S}= \overrightarrow{r_f}- \overrightarrow{r_i}$
= (4ĵ + 3k̂) – (–2î + 5ĵ)
= 2î – ĵ + 3k̂
$\overrightarrow{F}$ = 4î + 3ĵ
$\omega = \overrightarrow{F}. \overrightarrow{S}$ = (4î + 3ĵ) × (2î – ĵ + 3k̂)
= 8 – 3 = 5 J