How can scientists test their ideas about the origin of the universe if they cant physically interact with or study it

If a spring has a k value of 100 newtons per meter and it is stretched 0.50 meters, what is the restoring force of the spring?

Afeather of mass 0.001 kg falls from a height of 2 m. under realistic conditions, it experiences air resistance. based on what you know about friction, what can you say about the kinetic energy of the feather as it reaches the ground? acceleration due to gravity is g = 9.8 m/s2. a. ke < 0.0196 j b. ke = 00196 j c. je = 0 j d. ke > 0.0196 j

True or false graphs must include scales that increase by the same amount