In trial 1 of an experiment, a cart moves with speed v0 on a frictionless, horizontal track and collides elastically with another cart that is initially at rest. In trial 2, the setup is identical except that the carts stick together during the collision. How does the speed of the two-cart system’s center of mass change, if at all, during the collision in each trial?

Which number is main idea? i need answer quick. (1) people may think that love and romantic feelings are enough of a basis for choosing a spouse. (2) the chances of a marriage surviving, however, would improve if prospective marriage partners considered a few unromantic questions before deciding on matrimony. (3) for example, do the two individuals involved share a common socioeconomic background? (4) the more similar they are in their social, economic, religious, and cultural backgrounds, the more similar their expectations about married life will be. (5) in addition, what are their goals? (6) it’s a big advantage to the marriage if they know and share one another’s goals concerning career, lifestyle, and family. (7) finally, and maybe most important, how does the prospective spouse treat others in his or her life? (8) during the courtship, the boyfriend or girlfriend may get special consideration, but in the long run, spouses will probably treat each other about the same way they treat their own family members.

The volume of a cylinder is 72 tt cm3. if the radius is 3 cm, what is the height of the cylinder?

All of the following are examples of service-learning opportunities except: a. donating time to senior citizen war veterans and writing a report about the experience for your u.s. history class. b. getting a part-time job at a habitat restoration center. c. reading to second-grade students as part of your assigned reading time for your english class. d. planting trees in your community and then discussing global warming in your science class.