A 9,300kg railroad car traveling at a velocity of 15m/s strikes a second box car at rest. if two cars stick together and move off with a velocity of 6m/s what is the mass of the second car

A. they hold atoms  together with a molecule.its a force that exist between molecules. hope this .

Iknow the first part it is the average star i am not 100% sure

Answerthe energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.explanationwe define electric potential as the ratio electric potential energy to the charge,    then the following gives us the potential difference,      the formula  may be on your formula sheet.the change in electric potential energy would be the energy that would needed to move it from point a to point b. solving for that, we get    using q = 8.00  × 10⁻¹⁹ c and  δv = 2.00 v, we get    the energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.