logo

Ask Questions, Get Answers

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

Which of the following is true, if no work is done by a force on an object?

(1) the object is stationary
(2) the force is always perpendicular to its velocity
(3) the force is always perpendicular to its acceleration
(4) the object moves in such a way that the point of application of the force remains fixed

Can you answer this question?
 
 

1 Answer

0 votes
Answer: (1), (2) and (4)
Work done by a constant force $W= Fd \cos \theta$
(1) If the object is stationery even when the force is applied, $d = 0 \rightarrow W = 0$
(2) If the force is perpendicular to velocity $\rightarrow \theta = 90^\circ \rightarrow W = 0$, as $\cos 90 = 0$
(4) If the object moves in such a way that the point of application remains fixed then this is an example of circular motion, where the angle $\theta$ between force and displacement is $90^\circ \rightarrow W = 0$ (same math as (2))
(3) is not true as acceleration does not convet direction of displacement unlike velocity.
answered Aug 25, 2014 by balaji.thirumalai
 

Related questions

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