Projectile motion from the ground

[Scorry]

Homework Statement

The problem (5.9) and given data is attached.

Homework Equations

All relevant equations are given (5.9).

On (5.9) What does the s subscript y represent? And why does gravity equal -32?

The Attempt at a Solution

The solution is given. This is a scan problem.

 

[gneill]

They are using the variable s to represent distance (This is a common practice in some texts). So $s_y$ would be the distance in the "y" (vertical) direction. $32 ft/s^2$ is the gravitational acceleration using feet rather than meters for distance.

 

[Scorry]

Thank you gneill. Is the distance in the "y" vertical direction 0 because its final position is the ground?

 

[gneill]

Thank you gneill. Is the distance in the "y" vertical direction 0 because its final position is the ground?

It's 0 at the beginning and end of the trajectory, both at ground level.