Analyzing and clarifying groups of magnetic materials: Names of magnetic conductors, composition, characteristics, advantages and disadvantages, basic applications

What is the conversion factor between kg/m^3 and g/m^3. express your experimental values for the densities in kg/m^3.

A6,600 kg train car moving at +2.0 m/s bumps into and locks together with one of mass 5,400kg moving at -3.0m/s. what is their final velocity? +0.50 m/s -1.0 m/s +2.5 m/s -0.25 m/s

Aman tries to push a box of mass 4 kg with a force of 5 n but the box remains stationary if the coefficient of static friction is 0.45, what is the value of the maximum force of friction?