11@mani
hey then say what the answer is?
No work is done by a force on an object if
(a) the force is always perpendicular to its velocity
(b) the force is always perpendicular to its acceleration
(c) the object is stationary but the point of application of the force moves on the object
(d) the object moves in such a way that the point of application of the force remains fixed
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17 Answers
1b toh nahi ho sakta.
if F vector is perpendicular to A vector which is perpendicular to V vector and all lie on the same plane then F l l V.
1if the point of application moves on the object and the object doesn't move work done =0
s'pose we r pushing a well, work done=0
ab well ko dhakka dete uske charo taraf gol-gol ghum rahe hai, still work=0
3We can say dat a work is done on the object only when the object moves in the direction of the applied force.
so i think it shud be a,c,d
1hey see,
displace ment is S [vector]
so velocity || S
if F is perpendicular to v then F is perp to S
similarly for acceleration.
and D is correct becoz.... think about pure rolling, there friction does no work ..
no wtell the ans..