Which procedure did early chemists use to determine which substances were elements?

a.
they observed the way the materials looked.

b.
they physically broke down the elements they discovered.

c.
they broke down materials by chemical means.

d.
they observed the substances that made up individual atoms.

question: ray weighs 100 kilograms, his wrestling partner, bobby, weighs 50 kilograms. if ray moves at 4 m s , how fast will bobby have to run at him to apply an equal amount of kinetic energy?

answer: 8 m/s he needs to run twice as fast to keep up so he has some work to do

explanation:   if the mass has units of kilograms and the velocity of meters per second, the kinetic energy has units of kilograms-meters squared per second squared.

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(jacemorris04)