A ball falls freely from rest with an acceleration g. The variation with time t of its displacement s is given by s=1/2gt2 . The percentage uncertainty in the value of t is ±3% and that in the value of g is ±2%. What is the percentage uncertainty in the value of s.

Aheavy boy and a lightweight girl are balanced on a massless seesaw. the boy moves backward, increasing his distance from the pivot point. what happens to the seesaw? it is impossible to predict without knowing additional information. the side the boy is sitting on will tilt downward. the side the girl is sitting on will tilt downward. nothing; the seesaw will remain balanced.