Describe Motion Clearly Practice Test

A person walks on a moving walkway in an airport. The walkway moves north at $1.0\ \text{m/s}$ relative to the ground. The person walks north at $1.0\ \text{m/s}$ relative to the walkway. Which statement correctly describes the person’s velocity relative to the ground?

A bus moves east at $20\ \text{m/s}$ relative to the ground. A student on the bus throws a ball straight forward (east) at $5\ \text{m/s}$ relative to the bus. Which motion description is most clear and complete?​​