I don't think you mean 'criteria'. I think you mean three occurrences or
observations that indicate the presence of acceleration.
They are:
-- an object is speeding up
-- an object is slowing down
-- the direction of an object's motion is changing .
Any one of these changes is acceleration.
There's a single term that covers them all. It is "change in velocity".
Answer:9.75 m/s
Explanation:
Given
Length of ladder 
Foot the ladder is moving away with speed of 
From diagram
------1
at 


Now differentiating equation 1 w.r.t time




negative indicates distance is decreasing with time
Explanation:
Acceleration is the rate of change of velocity with time. When acceleration increases a body moves a faster velocity.
- In the graph acceleration at time t= 100s is rapidly increasing.
- At t = 20s, the acceleration of the body is getting started up.
A vehicle at time 100s will have a faster velocity compared to one at t = 20s
What are the "following" devices ? ?
I think they're a list of choices that you have but aren't sharing.
A few devices associated with the reception of various types of
radio signals include the resonant tank, the local oscillator, the
mixer, the detector, the coherer, the discriminator, the parabolic
reflector, the lecher wires, the audio transducer, the demultiplexer,
and ... my personal guess ... the 'antenna' or 'aerial'.