Consider the model above. it represents the electrical force. as r increases, the attractive force decreases. how would this model compare to a model for the force of gravity?

What is the role of the ocular lens?

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Asolid round steel rod 6.25 mm in diameter and 375 mm long is rigidly bonded to the end of solid square brass rod 25 mm on a side and 300 mm long. the geometric axes of the bare are along the same line. an axial tensile force of 5.4 kn is applied at the extreme ends of the assembly. for steel e = 200 gpa and for brass e = 90 gpa. determine the total elongation for the assembly.