RICE theorem applications
The major hypothesis of Rice theorem is that you are dealing with a set which is "extensional", or "semantically closed". Formally this requires that when the encoding of a TM $M$ belongs to the set, and $N$ is a TM equivalent to $M$, then the encoding of $N$ must also belong to the set.

Equivalence here means that the TMs $M,N$ terminate on the same inputs, with the same output (including acceptance).

Conditions like "halts in 50 steps" break equivalence, in general. I.e. it is possible that $M$ halts in 10 steps with output zero on every input, yet $N$ does the same after "wasting" 100 steps. So, Rice can not be applied to these.


  Questions like:- Turing machine makes at least five moves,It accepts a string input of length at least five ,TM halts for every input on length &lt;50 are all decidable.


No. The property "at least five moves" is decidable. The properties "accepts a string of at least five" and "halts for every input of length &lt;50" are NOT decidable. Indeed, these properties only care about the input/output behavior of the TM, hence if $M$ satisfies one of those, and $N$ is equivalent, then $N$ also satisfies the same property. So, Rice applies to those.