How do we aquire knowledge in science?

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.

By what primary heat transfer mechanism does the sun warm the earth?

Using the free-body diagram, calculate the net force acting on the sled. is the sled in a state of dynamic equilibrium?