The work done by the force F → = 6 i ^ + 2 j ^ N in displacing an object from r 1 → = 3 i ^ + 8 j ^ m to r 2 → = 5 i ^ − 4 j ^ m , is

F → = 6 i ^ + 2 j ^ r → = r → 2 - r → 1 = 5 i ^ - 4 j ^ - 3 i ^ - 8 j ^ = 2 i ^ - 12 j ^ W = F → · S → = ( 6 i ^ + 2 j ^ ) · ( 2 i ^ - 12 j ^ ) = - 12 J

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PhysicsW.E.P.Calculation of workEasy2 minPYQ_2020

PhysicsEasysingle choice

The work done by the force $\vec{F} = 6 \hat{i} + 2 \hat{j} N$ in displacing an object from $\vec{r_{1}} = 3 \hat{i} + 8 \hat{j} m$ to $\vec{r_{2}} = 5 \hat{i} - 4 \hat{j} m$ , is

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Answer:

Solution:

$\vec{F} = 6 \hat{i} + 2 \hat{j}$

$\vec{r} = {\vec{r}}_{2} - {\vec{r}}_{1} = 5 \hat{i} - 4 \hat{j} - 3 \hat{i} - 8 \hat{j}$

$= 2 \hat{i} - 12 \hat{j}$
$W = \vec{F} \cdot \vec{S} = (6 \hat{i} + 2 \hat{j}) \cdot (2 \hat{i} - 12 \hat{j})$
$= - 12 J$

Stream:JEESubject:PhysicsTopic:W.E.P.Subtopic:Calculation of work

⏱ 2mℹ️ Source: PYQ_2020

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