A cubic meter of air near saturation may contain 28 grams, or about 1.6 moles of water molecules at 30 °C, but only 8 grams, or about 0.44 mole of water molecules per cubic meter of air at 8 °C.

Agardener uses a wheelbarrow to move soil from a truck to his garden. on the first trip from the truck to the garden, the wheelbarrow is half-full of soil and the gardener applies a certain force to cause it to accelerate. on the second trip, the wheelbarrow is full of soil. although the gardener applies the same amount of force to the wheelbarrow, he cannot move it with the same rate of acceleration. what should the gardener do to move the wheelbarrow at the same rate of acceleration for the second trip?

Imagine you had to physically add electrons, one at a time, to a previously neutral conductor. you add one electron very easily, but the second electron requires more work. in your initial post to the discussion, explain why this is. also, what happens to the work needed to add the third, fourth, fifth, and subsequent electrons

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?