Question

1. george walks to a friends house. he walks 650 meters north, then realizes he walked too far. he turns around and walks 200 meters south. the entire walk takes him 540 seconds. what is his velocity? what is his displacement? 11) pete is driving down 7th street. he drives 155 meters in 19.5 seconds. assuming he does not speed up or slow down, what is his speed in meters per second? 12) a skateboarder rides 200 meters east in 40 seconds and then 200 meters west in another 40 seconds, ending up where they started. what is their average velocity for the whole trip?

Explanation:

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Step1: Calculate displacement

Displacement is the net change in position. He walks 650 meters North and 200 meters South. Net displacement $d = 650 - 200=450$ meters North.

Step2: Calculate velocity

Velocity $v=\frac{d}{t}$, where $d$ is displacement and $t$ is time. Given $t = 540$ seconds and $d = 450$ meters North. So $v=\frac{450}{540}=\frac{5}{6}\approx0.83$ m/s North.

Speed $s=\frac{d}{t}$, where $d$ is distance and $t$ is time. Given $d = 155$ meters and $t=19.5$ seconds. So $s=\frac{155}{19.5}\approx7.95$ m/s.

Average velocity $v_{avg}=\frac{\Delta x}{t_{total}}$. Since the skate - boarder ends up where they started, $\Delta x = 0$ (displacement is 0). Total time $t_{total}=40 + 40=80$ seconds. So $v_{avg}=\frac{0}{80}=0$ m/s.

Answer:

Displacement: 450 meters North
Velocity: $\frac{5}{6}\approx0.83$ m/s North

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