First slide

Work done by Diff type of forces

Question

A uniform force of $(3 \hat{i} + \hat{j}) N$ acts on a particle of mass 2 kg. Hence, the particle is displaced from $(2 i + k) m$ to position $(4 \hat{i} + 3 \hat{j} - \hat{k}) m$ The work done by the force on the particle is [NEET 2013)

Moderate

A

9 J
B

6 J
C

13 J
D

15 J

Solution

Given, force, $F = (3 \hat{i} + \hat{j}) N$
$r_{1} = (2 \hat{i} + \hat{k}) m and r_{2} = (4 \hat{i} + 3 \hat{j} - \hat{k}) m$
$∴ s = r_{2} - r_{1} = (4 \hat{i} + 3 \hat{j} - \hat{k}) - (2 \hat{i} + \hat{k})$
$= (2 \hat{i} + 3 \hat{j} - 2 \hat{k}) m$
$∴ W = F \cdot s = (3 \hat{i} + \hat{j}) \cdot (2 \hat{i} + 3 \hat{j} - 2 \hat{k})$
$= 3 \times 2 + 1 \times 3 + 0 = 6 + 3 = 9 J$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App