La frecuencia de una onda es 60hz y su velocidad, 30 m/s. calcula su longitud de onda

An object of dimensions 50 cm x 40 cm x 0.20 cm has a mass 60g. find its density in g/cm3 and kg/ m3

Considering only the earth's rotation, determine how much later the asteroid would have had to arrive to put the explosion above helsinki at longitude 25˚ e? this would have obliterated the city.

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.