What happens if the person on the cliff throws the rock straight down, instead of straight up? To explore this question, calculate the velocity of the rock when it is 5.10 m below the starting point, and has been thrown downward with an initial speed of 13.0 m/s.

Strategy
Draw a sketch.

Since up is positive, the final position of the rock will be negative because it finishes below the starting point at y₀=0. Similarly, the initial velocity is downward and therefore negative, as is the acceleration due to gravity. We expect the final velocity to be negative since the rock will continue to move downward.

Transcribed Image Text:

20= -13.0 m/s = -9.8 m/s² L X