How can you find out whether copper is harder of softer than the plastic used in a plastic cup

What is the function of the commutator in a dc motor? a. to spin the magnet b. to change direct current into alternating current c. to change alternating current into direct current d. to spin the wire coil

Which feature indicates that mars resides in the inner region of the solar system

All the simple machines make work easier to do by changing the or of a force. a. size; type b. work; type c. size; direction d. type; direction