Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
Home  >>  JEEMAIN and AIPMT  >>  Physics  >>  Class11  >>  Work, Power and Energy
0 votes

An object is displaced from point $A(2m,3m,4m)$ to a point B $(1m, 2m, 3m) $ under a constant force. $\hat F=(2 \hat i+3 \hat j+4 \hat k)$. Find the work done by the force

\[(a)\;-9\;J \quad (b)\;6 \;J \quad (c)\; 9 \;J \quad (d)\;-6\;J\]
Can you answer this question?

1 Answer

0 votes
$W=\hat F.\hat {ds}$
$\hat {ds}=\hat r_f-\hat r_i$
$\hat {ds}=(\hat i+2 \hat j+3 \hat k)-(2 \hat i+3 \hat j+4 \hat k)$
$\quad=(-\hat i-\hat j-\hat k)$
$W=(2 \hat i+3 \hat j+4 \hat k).(-\hat i - \hat j -\hat k)$
$\quad= -9 J$
Hence a is the correct answer. 


answered Aug 7, 2013 by meena.p
edited Feb 17, 2014 by meena.p

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App