Until a train is a safe distance from the station, it must travel at 5 m/s. once the train is on open track, it can speed up to 45 m/s. if it takes a train 8 seconds to reach 45 m/s, what is the acceleration of the train?
m/s2

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

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?

Ihave a density of 1.61g/cm^3 and a mass of 28g. find the missing value