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A uniform force of (3i^+j^)(3\hat{i} + \hat{j}) N acts on a particle of mass 2 kg. The particle is displaced from the position (2i^+k^)(2\hat{i} + \hat{k}) m to the position (4i^+3j^k^)(4\hat{i} + 3\hat{j} - \hat{k}) m. The work done by the force on the particle is:

A

6 J

B

13 J

C

15 J

D

9 J

Step-by-Step Solution

According to the definition of work done by a constant force, work (WW) is the scalar product of the force vector (F\mathbf{F}) and the displacement vector (d\mathbf{d}), expressed as W=FdW = \mathbf{F} \cdot \mathbf{d} .

  1. Find the displacement vector (d\mathbf{d}): Displacement is the difference between the final position (r2\mathbf{r_2}) and the initial position (r1\mathbf{r_1}) . d=r2r1=(4i^+3j^k^)(2i^+k^)\mathbf{d} = \mathbf{r_2} - \mathbf{r_1} = (4\hat{i} + 3\hat{j} - \hat{k}) - (2\hat{i} + \hat{k}) d=(42)i^+(30)j^+(11)k^=2i^+3j^2k^ m\mathbf{d} = (4-2)\hat{i} + (3-0)\hat{j} + (-1-1)\hat{k} = 2\hat{i} + 3\hat{j} - 2\hat{k} \text{ m}

  2. Calculate the scalar product: Multiply the corresponding components of the force F=(3i^+j^+0k^)\mathbf{F} = (3\hat{i} + \hat{j} + 0\hat{k}) N and the displacement vector . W=(3)(2)+(1)(3)+(0)(2)W = (3)(2) + (1)(3) + (0)(-2) W=6+3+0=9 JW = 6 + 3 + 0 = 9 \text{ J}

Thus, the work done by the force is 9 J.

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