a ball is dropped from rest off a cliff of height 50m, determine the final velocity of the ball assuming no air resistance.

Consider the appropriate equation of motion to solve this (use SUVAT method). The equation v^2=u^2+2as is appropriate to solve. Substituting in the knowns gives v=+sqrt(29.8150)=31.32 which, quoted to the correct number of significant figures is 30m/s