Which simple experiment could be conducted to show an example of how lightning is created? a) rub a balloon so it picks up extra electrons from the sweater or your hair and becomes slightly negatively charged. b) rub a balloon filled with air on a wool sweater or on your hair. then hold it up to a wall. c) connect the positive pole of an electrical source to the negative pole, so you create a circuit. d) walk across a carpet, shuffling your feet and touching something made of metal. eliminate

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

In a system, when potential energy decreases, then entropy also decreases. true false

World class speed skaters can skate a 3,000-m course in about 4 minutes.what is their average speed for this course? a. 12.5 m/sb. 1.33 m/sc. 1.25 m/sd. 13.3 m/s