Please answer he questions

"Work done by a constant force on an object is the product of the force and the distance moved by the object in the direction of the force" -textbook

There is work done ONLY if the direction of the force and the direction the item is moving are the same. In figure A, the direction of the force (the lifting) is upwards (defying gravity), and the book is moving upwards, so work is done. In figure B, the force is still moving upwards (the person is carrying the books) but the book is moving to the right, so there is NO work done.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

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