The diagram above represents two forces acting on an object.
which expression represents the total force on the block?
a)
20n + 10n
b)
20n x 10n
c)
10n + -20n
d)
12n/10n

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ