What is a sample that is treated exactly like the other experimental groups except that the independent variable is not applied to it is called ?

The energy equivalent of the rest mass of an electron is

Achild has maximum walking speed of 1.6 m/s. what is the length of the child's legs? 0.26 m

While carrying a heavy box up the stairs,you set the box on a step and rest. then you pick up the box and carry it to the top of the stairs. describe these actions in terms of balanced and unbalanced forces acting on the box.