A 30 cm spring with constant 70 N/m is compressed to 10 cm and placed between two carts. Cart A mass m5kg andmp is unknown. Initially the system is at rest. After it is released it is observed that cart A has three times the velocity of cart B. 1. a) What force must be exerted initially to keep the spring compressed? b) What is the work done to compress the spring? c) By considering conservation of momentum determine the mass m d) By considering conservation of energy find the velocities of the carts A and B after the spring is released

Ateam of astronauts is on a mission to land on and explore a large asteroid. in addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. with what minimum initial speed vesc will the rocks need to be thrown in order for them never to "fall" back to the asteroid? assume that the asteroid is approximately spherical, with an average density p 3.84 x108 g/m3 and volume v 2.17 x 1012 m3 recall that the universal gravitational constant is g 6.67 x 10-11 n m2/kg2

The current in a hair dryer measures 11 amps. the resistance of the hair dryer is 12 ohms. what is the voltage?unit:

What changes occur in the brain during the teenage years? 25 points, someone me out!a.) thinking becomes slower as the brain grows larger. b.) connections between neurons become stronger and faster. c.) unused neurons fuse together to form larger, better functioning neurons. d.) more neurons are developed.