Answer:
gravity is the invisible force that attracts us the the earth\
1.normal force 2.frictional force 3. spring forces
flowing electrons produce a magnetic field
unbalanced forces are not equal they always cause changes in the moving object like the direction . balanced forces are equal and cause no changes
The SI system, also called the metric system, is used around the world. There are seven basic units in the SI system the meter kilogram second (s), kelvin the ampere , the mole and the candela.