What happens to collagen and elastic fibers during aging?

You hang a book bag on a spring scale and place the bag on a platform scale so that the platform scale reads 23.7n and the spring scale reads 13.8n. what is the magnitude of the force that earth exerts on the bag?

Is there a point between a 10 nc charge and a 20 nc charge at which the electric field is zero?

What quantity do units represent in value