Question

A student walks east 100 meters in 2 minutes. She then walks north 200 meters in 4 minutes. Which statement is true?

Her velocity is constant because her speed is constant
Her velocity is constant because her direction is constant
Her velocity changes because her speed varies
Her velocity changes because her direction changes

Answer 1

To analyze the student's motion, we need to consider the definitions of speed, velocity, and how they relate to each other.

1. **Speed** is a scalar quantity and measures how fast an object is moving, regardless of its direction.
2. **Velocity** is a vector quantity that includes both speed and direction.

In this case, the student first walks east at a speed of 100 meters in 2 minutes, which is a constant speed. Then, she walks north at a speed of 200 meters in 4 minutes, which is also a constant speed.

However, while her speed remains constant in each segment of her walk, her velocity changes because her direction changes (from east to north).

Therefore, the correct statement is:

**Her velocity changes because her direction changes.**