Velocity Speed
1. **Problem statement:** Given a displacement-time graph with piecewise linear segments, find the velocity and speed for each segment.
2. **Key formulas:**
- Velocity $v = \frac{\Delta d}{\Delta t}$ (displacement change over time change)
- Speed is the magnitude of velocity, so $\text{speed} = |v|$
3. **Analyze each segment:**
- Segment 1: from $t=0$ to $t=5$, displacement changes from $0$ to $5$ meters.
$$v_1 = \frac{5 - 0}{5 - 0} = \frac{5}{5} = 1\ \text{m/s}$$
Speed $= 1$ m/s
- Segment 2: from $t=5$ to $t=12$, displacement remains constant at $5$ meters.
$$v_2 = \frac{5 - 5}{12 - 5} = 0$$
Speed $= 0$ m/s
- Segment 3: from $t=12$ to $t=17$, displacement increases from $5$ to $13$ meters.
$$v_3 = \frac{13 - 5}{17 - 12} = \frac{8}{5} = 1.6\ \text{m/s}$$
Speed $= 1.6$ m/s
- Segment 4: from $t=17$ to $t=20$, displacement remains constant at $13$ meters.
$$v_4 = \frac{13 - 13}{20 - 17} = 0$$
Speed $= 0$ m/s
- Segment 5: from $t=20$ to $t=30$, displacement decreases from $13$ to $0$ meters.
$$v_5 = \frac{0 - 13}{30 - 20} = \frac{-13}{10} = -1.3\ \text{m/s}$$
Speed $= |-1.3| = 1.3$ m/s
4. **Summary:**
- Velocities: $v_1=1$, $v_2=0$, $v_3=1.6$, $v_4=0$, $v_5=-1.3$ m/s
- Speeds: $1$, $0$, $1.6$, $0$, $1.3$ m/s
Velocity indicates direction; speed is always positive.