Rítmo o ritmo?
Comenzaron a tocar la guitarra y a cantar. Sí, era el mismo rítmo, la misma melodía y la misma pasión. Why does ritmo have an accent, a misprint here?
If the spoken accent falls on the next to last syllable - which it does in the case of 'ritmo' you only need a written accent (tilde) over the vowel if the word does NOT end in a 'n, s, or vowel'. In this case, 'ritmo' DOES end in a vowel (o) so you do not need a written accent. There's two other general rules for accents, but they don't pertain to this case.
Look at the case of 'dólar' the spoken accent falls on the next to last syllable on the letter 'o'. It doesn't end in a 'n, s or vowel' so this time you DO put a written accent.
Hope that helps.
The word is grave so the accent falls on the "I" according to the rules of intonation. Since that is where you want it, no accent mark is needed.