Pick the correct statements : (a) Average speed of a particle in a given time is never less than the magnitude of the average velocity.
Answers
Correct statements r (a),(b),(c)
Validity statement for (a)
The average velocity is displacement /time but average speed is distance/ time. Since distance is always greater than or equal to displacement, it is evident that average speed is either equal to or greater than average velocity
Valdity staement for (b)
Situation b simplay states that a situation should exist where the magnitutde of acceleration is not equal to 0 but velocity is 0. Such a situation is indeed possible when we accelerate a car frm rest.Initially the car is at rest but it has a positive acceleration
Valdity staement for (c)
When a particle moves in a uniform circular motion, after completing 1 complete revolution its velocity is 0 but throughout the journey its has a certain instantaneous velocity.
Contradiction satment for (d)
If the average velocity for the particle is 0 then the displacement is essentially . For making 0 displacement either it should be at rest (no possible as instaneous velocity is never 0 acc to question)
or it should have to revesed its doirection. However if it revesed the direction or had simply deaccelerated during the motion , it would surely reach a state when it will have 0 instaneous velocity. So it is the incorrect statement.