A blue whale materializes 11.5 km above an airless planet with an acceleration of gravity of 6.85 m/s2. What is the speed of the whale right before impact? (Work-Energy Theorem)
mgh=mv^2/2
v= sqr(2gh) =sqr(2•6.85•11500) =397 m/s
v= sqr(2gh) =sqr(2•6.85•11500) =397 m/s