A10 cm long spring is attached to the ceiling. when a 2.0 kg mass is hung from it, the spring stretches to a length of 15 cm.
a. what is the spring constant k?
b. how long is the spring when a 6.0 kg mass is suspended from it?

In a good thermo flask the main cause of heat loss is

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.

Aplane flying horizontally at an altitude of 1 mile and a speed of of 500mih passes directly over a radar station. find the rate at which the distance from the plane to the station is increasing when it is 2mi away from the station.