Which example describes linear motion as related to human movement?

• A. A gymnast twirling through the air
• B. A sprinter running down the track
• C. A figure skater spinning on the ice
• D. A basketball player doing a 360-degree slam dunk

Answer: (B)

Translational (linear) motion describes movement where the whole body travels through space in the same direction along a path, with the center of mass moving forward. A sprinter running down the track exemplifies this because the body’s overall movement is a forward translation along the track—the center of mass follows a relatively straight line as speed increases. The other examples center on rotation around a point or axis: a gymnast twirling through the air and a figure skater spinning on the ice are angular motions, where parts of the body rotate around a fixed axis. A basketball player performing a 360-degree slam dunk also emphasizes rotation, even though there is vertical lift involved, since the primary action described is spinning about an axis.