What is the equation for kinetic energy of a bicycle?

[aron silvester]

Homework Statement

How did they get mv^2? Where did the 1/2 go? I tried working out the equation below the question and I ended up getting (1/2)mv^2.
Look at the image to see. It's the rotational kinetic energy formula.

Homework Equations

It's in part 1

The Attempt at a Solution

It's in part 1

 

[TSny]

Their mv² came from combining ½mv² + ½mv²