Which statement is true for both electromagnetic waves and mechanical waves

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.

Smallest intensity of a stimulus that you can detect 50 percent of the time is

Ascientist wants to test ways to reduce pollution in lake . what is the bestway of doing this