A body is moving with a uniform acceleration of 2 m/s2. What does it mean?

It means that the body is moving, and getting faster and faster. At any time, it's moving 2 m/s faster than it was moving 1 second earlier.

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."