If f=ma, what is the value of f when m=5 and a=3?

The answer is:  15 .
                                               
{Note:  If this is a physics problem ; and the formula: "F = m*a" is for:  
    "Force = mass * acceleration" ;  be sure that the correct units are used!}.

Explanation:

 F = m * a ;

Given m = 5 ;
        
           a = 3 ;

 F = 5 * 3 = 15 .

A, motor

Step-by-step explanation: