posted by Andy .
A child operating a radio-controlled model car on a dock accidentally steers it off the edge. The car's displacement 0.95 s after leaving the dock has a magnitude of 6.7 m. What is the car's speed at the instant it drives off the edge of the dock?
displacement is the change in position from top of dock to the place it hit. You can figure the vertical distance from the time fallng.
vertical fall=1/2 g t^2 solve for that.
displacemetn^2=verticalfall^2 + horizntaldistance^2
so solve that for horizontaldistance, you know the other two.
now solve for speed.