What is the molecular formula of a compound that has a molecular mass of 54 and the empirical formula is c2h3

To find the molecular formula from the empirical formula, you need to find a multiple (x) that will give you the molar mass of the compound which in the question is 54 g/mol.

If C₂H₃ is the empirical formula
 molar mass of empirical formula = (12 × 2) + (1 × 3) g/mol
                                                     =  27 g/mol
let x = multiple
let molecular formula = C₂ₓ H₃ₓ

            multiple = molecular mass ÷ empirical mass
                         =  54 g/mol ÷  27 g/mol
                         =  2

If molecular formula = C₂ₓ H₃ₓ

then molecular formula = C₂₍₂₎H₃₍₂₎

                                      = C₄H₆

Okay well gravitational energy is matter forced by gravity making energy though the kinetic energy then the electric energy produces electricity from the kinetic energy and the kinetic energy gets its energy from the gravitational energy. was that the answer you wanted or something else?  

Depends on the speed of the car.