A car travels 15 km east at a constant speed of 20 km/hr, then continues east for 20 km at a constant speed of 30 km/hr. What can be said about the magnitude of average velocity?

V_{a v g} . > 27 k m / h r

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V_{a v g} . < 27 k m / h r

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V_{a v g} . = 27 k m / h r

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Solution

The correct option is B $V_{a v g} . < 27 k m / h r$
$t_{4}$ = time interval with speed of 20 km/hr
$= \frac{15}{20} = 0.75 h r$
$t_{2}$ = time interval with speed of 30 km/hr
$= \frac{20}{30} = 0.66 h r$
$∴ a v g v e l = \frac{20 + 15}{\frac{15}{20} + \frac{20}{30}} = 24.71 k m / h r < 25$

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A car travels 15 km east at a constant speed of 20 km/hr, then continues east for 20 km at a constant speed of 30 km/hr. What can be said about the magnitude of average velocity?

The correct option is B Vavg.<27km/hrt4 = time interval with speed of 20 km/hr =1520=0.75 hr t2 = time interval with speed of 30 km/hr =2030=0.66hr ∴avg vel=20+151520+2030=24.71 km/hr<25

The correct option is B $V_{a v g} . < 27 k m / h r$
$t_{4}$ = time interval with speed of 20 km/hr
$= \frac{15}{20} = 0.75 h r$
$t_{2}$ = time interval with speed of 30 km/hr
$= \frac{20}{30} = 0.66 h r$
$∴ a v g v e l = \frac{20 + 15}{\frac{15}{20} + \frac{20}{30}} = 24.71 k m / h r < 25$