Question

A particle acted upon by constant forces and $3 \hat { i } + \hat { j } - \hat { k }$ is displaced from the point $\hat { i } + 2 \hat { j } + 3 \hat { k }$ to point $5 \hat { \mathrm { i } } + 4 \hat { \mathrm { j } } + \hat { \mathrm { k } }$ . The total work done by the force in SI unit is :

• A. 20
• B. 40
• C. 50
• D. 30

Answer 1

Answer: (B)

40

Answer 2

Here,

$\overrightarrow { \mathrm { r } } _ { 2 } = 5 \hat { \mathrm { i } } + 4 \hat { \mathrm { j } } + \hat { \mathrm { k } }$

Displacement,

Work done by the forces,