Extremely large main sequence stars consume their fuel quickly and burn hot and bright. As they consume all their hydrogen, they become supergiants. Describe the changes that take place, in terms of luminosity and temperature, to these large main sequence stars as they exhaust their hydrogen supplies.

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.