An aluminum wire of varying thickness is pulled at each end with a force of 30 N. Which of the following statements is true? Note: tension is a force that tends to stretch something, and stress is the force per unit area.
a) The tension is 60 N all along the wire, and stress is constant along the wire
b) The tension is 60 N all along the wire, and stress varies along the wire
c) The tension is 30 N all along the wire, and stress is constant along the wire
d) The tension is 30 N all along the wire, and stress varies along the wire