Questions & Answers about Uusi keihäs painaa 800 grammaa.
Measurements in affirmative sentences use the total object case, but grammaa is partitive. Why is that?
The grammatical object here is actually the number kahdeksansataa (800). For numerals other than one, the total object form looks exactly like the basic nominative case. The word grammaa is partitive simply because it follows a number greater than one, not because of the verb.
How would the object cases look if the javelin weighed exactly one gram?
It would be painaa yhden gramman. The number one (yksi) behaves like a normal noun and takes the genitive-looking accusative form (yhden) to show it is a total object. The unit of measurement must agree with it, so it becomes gramman.
What happens to the case of the measurement if we make the sentence negative?
Negative sentences always require a partitive object. The number itself would change to the partitive case, so you would say ei paina kahdeksaasataa grammaa (does not weigh 800 grams).
Does the verb painaa always take a total object?
It takes a total object when expressing an exact weight, as in this sentence. However, if you use the other meaning of painaa (to press or push), it typically takes a partitive object because the action is continuous. For example: Hän painaa nappia (He is pressing the button).