Hey guys <3 I need some help with this performance task,, physics isn’t my strongest subject so help is much appreciated :)

(4/9 parts)

What property is a characteristic of a substance that can be observed and does not change the identity of the substance

The slope of a velocity time graph over any interval of time gives the during that interval

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.