Question

Give an example for a situation in which in a given time interval, instantaneous acceleration is never zero but average acceleration turns out to be zero.

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Answer 1

Average acceleration:-When the velocity of an object is changing continuously with different rate as like

a car from rest cover 20m/s speed in 5sec ,,then 30 m/s in 1s,then 80m/s in 8s

u can see here ,,the rate if Changing the velocity is different,i.e there is different acceleration for different time

the actual formula for average acceleration is

$\frac{v2 - v1}{t2 - t1}$

The average acceleration will be zero,if V2-V1=0

this can be possible when V2=V2

Instantaneous acceleration:-It is the Acceleration at any instant or at any moment of time

It is eqaul to ∆V/∆t

Example in which instantaneous acceleration is not zero,,but average acceleration is zero

consider a car starts moving with velocity 10m/s.The velocity of car is increasing continuously upto time 2min,,,then due to crowdy area it starts to decelerate and its velocity again became 10m/s in time of 3min

in this case average acceleration=10-10/180-0=0

instantaneous acceleration is the acceleration at any instant,,,

since at every moment of time the velocity of car continuously changes,,so ∆v will Never be zero

hence

instantaneous acceleration will never be zero

Answer 2

Answer:

Consider a simple example when we start a vehicle, initially we have zero velocity but have non zero acceleration ( that is why vehicle will start moving). If we drop a ball from some height above the Earth surface the velocity at that instant is zero but acceleration is non zero(gravity) which acts downward.