Nancy Carlson 
Harriet and the Roller Coaster, 2nd Edition [PDF ebook] 

Hang on-Harriet’s on her way up! For days, George has been taunting Harriet about the roller coaster at the amusement park. "It’s so big, you can’t see the top…It goes so fast, you might fall out…You’ll be too scared to ride on it." "I am NOT scared, " Harriet tells him. But that night she doesn’t sleep very well. And the next morning, when it’s time to go, she feels a little sick. Children are certain to recognize Harriet’s terror and cheer her spunk. And while she conquers her fear, Harriet will conquer her readers’ hearts as well.