Question

kai was 200 meters north of the library when he remembered he had to return some books to the library. it took him 200 seconds to do the round trip. which best describes kais round - trip? his speed was 1 m/s, and his velocity was 0. his speed was 2 m/s, and his velocity was 0. his speed was 1 m/s, and his velocity was 1 m/s north. his speed was 2 m/s, and his velocity was 2 m/s south.

Explanation:

Step1: Calculate the total distance

Kai goes 200 meters to the library and 200 meters back, so the total distance $d = 200+200=400$ meters.

Step2: Calculate the speed

Speed is calculated by the formula $v_{speed}=\frac{d}{t}$. Given $d = 400$ meters and $t = 200$ seconds, then $v_{speed}=\frac{400}{200}=2$ m/s.

Step3: Calculate the velocity

Velocity is a vector quantity. Since Kai returns to his original - starting position, the displacement $\Delta x=0$. The formula for velocity is $v_{velocity}=\frac{\Delta x}{t}$. So $v_{velocity}=\frac{0}{200}=0$ m/s.

Answer:

His speed was 2 m/s, and his velocity was 0.