A65 kg roller-blade is accelerating at 5 m/s/s across the side walk. what force would be necessary for this acceleration to occur?

this allows people to make the best decision or pursue the best option. when alternatives are weighed using their advantages and disadvantages, the option whose disadvantages outweigh the advantages (based on a qualitative or quantitative analysis) are shunned while those whose advantages outweigh their disadvantages are pursued.  

a.) travels faster in solids because the particles are closer together.

air is a gas water is a liquid