Solving a Physics Problem

With the collection of programs that we now have, solving a simple physics problem becomes easy. We assume that we have values for some variables and want the value of another variable:

What is the radius of a circle with area = 10

• Make a list (set) of the variables in the problem (desired variable and variables whose values are given).

  
  (radius area)
  

• Find an equation that involves those variables.

  
  (= area (* 3.14159 (expt radius 2)))
  

• Solve the equation for the desired variable.

  
  (= radius (sqrt (/ area 3.14159)))
  

• evaluate the rhs of the equation for the given values.

  
  1.78412