Given that Qc = 100J and QH = 250J, what is the work done?

Describe uniform velocity and variable velocity in short

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?

This is the substance(s) formed in a chemical reaction.