Answer:
Come on, Sammy, pedal this bike faster!
Step-by-step explanation:
Commas are used when addressing people directly. In this case, the speaker is talking to Sammy and is asking him to cycle more quickly. As a result, the name of the person is surrounded by commas because it is in the middle of the sentence. Thus, the addressed person's name is separated from the speaker's message to him.
The correct version of the rest of the sentences is the following:
Go, team, go!
Officer, I am sure I was going only 55 miles per hour.
Now then, naughty dog, what is your excuse for chewing this shoe?