Asled of mass m is coasting on the icy surface of a frozen river. while it is passing under a bridge, a package of equal mass m is dropped straight down and lands on the sled (without causing any damage). the sled plus the added load then continue along the original line of motion. how does the kinetic energy of the (sled + load) compare with the original kinetic energy of the sled? a) it is 1/4 the original kinetic energy of the sled. b) it is 1/2 the original kinetic energy of the sled. c) it is 3/4 the original kinetic energy of the sled. d) it is the same as the original kinetic energy of the sled. e) it is twice the original kinetic energy of the sled.

In the future, people will only enjoy one sport: electrodisc. in this sport, you gain points when you cause metallic discs hovering on a field to exchange charge. you are an electrodisc player playing the popular four disc variant. the disks have charges of qa = −8.0 µc, qb = −2.0 µc, qc = +5.0 µc, and qd = +12.0 µc. (1) you bring two disks together and then separate them. you measure the resulting charge of these two disks and find that it is +5.0 µc per disk. which two disks did you bring together? (a) a and b (b) a and c (c)a and d (d)b and c(e) b and d (f) c and d. (2) you bring three disks together and then separate them. you measure the resulting charge of these three disks and find that it is +3.0 µc per disk. which three disks did you bring together? a, b, and c (a) a, b, and d (c) a, c, and d (d) b, c, and d. (3) given the resulting charge of each disk measured in (b) is +3.0 µc, how many electrons would you need to add to a disk of this charge to electrically neutralize it? electrons