Second Above poster.
The "strength" of a cadence actually refers to dynamics, stress, and things of that nature. Sometimes the strongest cadence is a short one, like in Beethoven's fifth (arguably long)
If I play V7 - I with the soprano resolving up (leading tone) to the tonic with the bass landing on the tonic I can increase or decrease the strength of it by playing it again, using a "cadential extension" by playing the bass note again or playing a scale and repeating the cadence, holding the I chord longer than the V7, trilling the top note, using suspensions, etc...
The first thing you