Numerical Calculations with Units

The Wolfram Language's unit system utilizes various numerical methods, facilitating calculations using Quantity expressions within the Wolfram Language's numerical functions.
numerical approximation of the specified quantity
search for a numerical solution to an equation, starting with
search for a maximum of f, starting with
Numerical functions that operate on Quantity expressions.
N[quantity] gives you a numerical approximation of quantity:
For numerical functions like FindRoot and FindMaximum, if a variable is specified within a Quantity expression, then that variable is assumed to be a dimensionless value (representing the magnitude of its Quantity). If no unit is specifically associated with a variable, these functions will attempt to automatically determine the units associated with the variable, based on the expression and any specified start values.
Specifying x within a Quantity indicates that x is a dimensionless value:
Find the time it takes for a falling body to hit the ground:
Find a local maximum, starting the search at x=2:
Find the peak height of a bullet fired from a rifle vertically, without dampening:
Find how long it takes the bullet to return to Earth:
Find the maximum height of a body shot vertically upward, with dampening: