Two children push on heavy crate that rests on a basement floor. one pushes horizontally with a force of 150 n and the other pushes in the same direction with a force of 180 n. the crate remains stationary. show that the force of friction between the crate the floor is 330 n.

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.