Question

(2) use the diagram below to determine the average speed and velocity of the woman as she walks from point a to point b and then to point c in 35 seconds.

Explanation:

Step1: Calculate total distance

The woman moves from $A(- 10m)$ to $B(10m)$ and then to $C(-20m)$. The distance from $A$ to $B$ is $|10 - (-10)|=20m$, and from $B$ to $C$ is $| - 20 - 10| = 30m$. So the total distance $d=20 + 30=50m$.

Step2: Calculate average speed

The formula for average speed $v_{s}=\frac{d}{t}$. Given $t = 35s$ and $d = 50m$, then $v_{s}=\frac{50}{35}=\frac{10}{7}\approx1.43m/s$.

Step3: Calculate displacement

The displacement $\Delta x$ is the straight - line distance from the initial point $A(-10m)$ to the final point $C(-20m)$. So $\Delta x=-20-(-10)=-10m$.

Step4: Calculate average velocity

The formula for average velocity $v_{v}=\frac{\Delta x}{t}$. Given $t = 35s$ and $\Delta x=-10m$, then $v_{v}=\frac{-10}{35}=-\frac{2}{7}\approx - 0.29m/s$.

Answer:

Average speed: $\frac{10}{7}m/s\approx1.43m/s$
Average velocity: $-\frac{2}{7}m/s\approx - 0.29m/s$