Q129 / 160 · TS EAMCET 2020 (10 Sep Shift 2) · Physics

A force $\mathbf{F}=(2 \hat{\mathbf{i}}+4 \hat{\mathbf{j}}) \mathrm{N}$ is applied on an object of mass $M$. What is the work done by this force in moving the object horizontally along the $X$-axis by $3 \mathrm{~m}$ ?

  • A
    $2 \mathrm{~J}$
  • B
    $4 \mathrm{~J}$
  • Correct answer
    C
    $6 \mathrm{~J}$
  • D
    $8 \mathrm{~J}$

Solution

Displacement of object is along $X$-axis by $3 \mathrm{~m}$, $\mathbf{x}=3 \hat{\mathbf{i} m}$ $\text { Force }=2 \hat{\mathbf{i}}+4 \hat{\mathbf{j}} \mathrm{N}$ Work done by force, $W=\mathbf{F} \cdot \mathbf{x}=(2 \hat{\mathbf{i}}+4 \hat{\mathbf{j}}) \cdot 3 \hat{\mathbf{i}}=6 \mathrm{~J}$

Hence, the correct answer is option: 'C'.

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