Question

what is the difference between per hour, a hour and each hour​

Answer 1

Answer:

hope it will help u ❣️

Explanation:

In this sentence, the preposition in needs to be followed by a noun phrase; an hour works as a noun phrase, but per hour is a preposition phrase, so it's ungrammatical. In other words, you can distinguish the two syntactically.

Answer 2

Answer:

used in measurements that describe the speed of somethingThe speed limit is 65 miles per hour.

At every hour exactly; one o'clock, two o'clock, and so on. For example, The shuttle to New York departs on the hour. An extension of this idiom is every hour on the hour, meaning every time the clock's big hand reaches twelve, as in The bus passes by the house every hour on the hour.