When a certain amount of blue light and red light shine on a metal surface, only blue light produces an electric current. Write a paragraph describing how increasing the intensity of each light will affect the amount of current produced. How does quantization help explain these observations?

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.