Which of the following are sources of mechanical energy?

A33.1 g copper object is launched from a 1.5 m 30° steel incline positioned on the floor by being pulled up a string attached to a 50.0 g mass suspended vertically over a pulley. the object is projected towards a glass table where it lands when it is at the point along its trajectory with the lowest speed. it comes to a halt when it clears the opposite edge of the table. it then falls and lands on 9 physics texts each 5 cm thick that are stacked on the floor on the opposite side of the table. assume that the table does not have a ledge and the rectangular object experiences 0.05 n of air resistance as it falls towards the books. how far and how long did the object travel and how fast does it hit the books. assume that at the moment the copper object leaves the incline, the massless string and ideal pulley break off

Animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. reactivate d) a dog is getting hot in the sunlight, so he moves to a shaded area.

If an electric circuit is not grounded it is best to reach out and touch it to provide the ground a.true or b.false