Before a race, an athlete warms up by jogging around the track shown below at a constant rate of 2.3 m/s.

Question

What statement best describes his motion as he jogs around the curved part of the track?
A.
His speed changes, but his velocity stays the same.
B.
His speed and velocity both change.
C.
His speed stays the same, but his velocity changes.
D.
His speed and velocity both stay the same.

Answer 1

To analyze the athlete's motion as he jogs around the curved part of the track, we need to consider the definitions of speed and velocity:

• Speed is a scalar quantity that refers to how fast an object is moving, regardless of its direction. In this case, the athlete's speed is constant at 2.3 m/s.

• Velocity is a vector quantity that includes both the speed of an object and its direction of motion. As the athlete jogs around a curve, even though his speed remains constant at 2.3 m/s, his direction is changing continuously.

Since the direction of the athlete's motion changes as he jogs around the curve, his velocity changes even though his speed does not.

Therefore, the best statement that describes his motion as he jogs around the curved part of the track is: C. His speed stays the same, but his velocity changes.