Question

26 points. Pls, hurry. When you lift a book from the ground to your desk, what kind of work do you do, negative or positive? By lifting the book, what do you change? Does the book gain or lose energy? What kind of energy?

Second question: A ball with a mass of 5.0g is moving at a speed of 2.0 m/s. Would doubling the mass or doubling the speed have a greater effect on the kinetic energy of the ball? Explain.

Answer 1

Negative kind of work can be done.

Answer 2

2. Doubling the mass would have a greater effect of the kinetic energy of the ball because you are dividing the mass by velocity, and if you have a greater mass that means a bigger answer. If you have a bigger velocity or denominator, that means less of a product which would be kinetic energy in this case.