Billy runs to his high school crush Juanita who is 20.0m in from of him in 5.0s. He asks her for a kiss but gets a slap instead and runs 40.0m back to his mama in 5.0s. What is Billy’s average velocity? Assume forward is positive and back is negative.

You have been hired to design a spring-launched roller coaster thatwill carry two passengers per car. the car goes up a 10-m highhill, then descends 15m to the track's lowest point. you'vedetermined that the spring can be compressed a maximum o 2.0m andthat a loaded car will have a maximum mass of 400kg. for safetyreasons, the spring constant should be 10% larger than the minimumneeded for the car to just make it over the top. a) what spring constant (k) should you specify ? b) what is the maximum speed of a 350 kg car if the spring iscompressed the full amount.