Posted by **ben** on Sunday, September 10, 2006 at 5:14pm.

You drive on an interstae 10 from San Antonio to Huston, half the [b]time[/b] at 55km/h and the other half at 90km/h. On the way back you travel half the [b]distance[/b] at 55km/h and the other half at 90km/h.

What is your average speed from San Antonio to Houston

What is your speed from houston to San Antonio?

c) speed for entire trip

d) What is your average velocity for the whole trip?

Let T = total time of trip and D = toal distance covered

average speed = distance/time

(a) SA to Houston:

V1 = 55*(T/2)+90*(T/2) / T = (55+90)/2) = ?

(b) Houston to SA:

V2 = D/[(D/2)(1/55)+(D/2)(1/90)]

= 2/[(1/55) + (1/90)]

(c) 2D/[D/V1 + D/V2]=

2/[1/V1 = + 1/V2)]

(d) Think about the definition of velocity. You end up where you started in this case. Vector displacement = 0.

- physics -
**Anonymous**, Tuesday, September 4, 2012 at 7:32pm
72.5 km/hr

## Answer This Question

## Related Questions

- science - You drive on an interstae 10 from San Antonio to Huston, half the [b]...
- Physics - Tim and Rick both can run at speed Vr and walk at speed , Vw with Vr &...
- physics - a point moving on a straight line traversed half the distance with a ...
- physics - a body travelling along a straight line travels one half of the total ...
- physics - A baseball leaves a pitcher's hand horizontally at a speed of 115 km/h...
- physics - A baseball leaves a pitcher's hand horizontally at a speed of 115 km/h...
- chemistry - The half-equivalence point of a titration occurs half way to the end...
- chemistry - The half-equivalence point of a titration occurs half way to the end...
- Chemistry - The half-equivalence point of a titration occurs half way to the end...
- Math - A car is traveling south at a speed of 68 mi/h from Dallas toward San ...

More Related Questions