A particle covers half of its total distance with speed $\nu_{1}$ and the rest half distance with speed $\nu_2.$ Its average speed during the complete journey is (2002)

$\frac {v_1^2v_2^2}{v_1^2+ v_2^2}$

$\frac {2v_1v_2}{v_1+ v_2}$

$\frac {\nu _{1}+ \nu _{2}}2$

$\frac {\nu _{1}\nu _{2}}{\nu _{1}+ \nu _{2}}$

None

A car covers the first half of the distance between two places at 40 km/h and another half at 60 km/h. The average speed of the car is

40 km/h

48 km/h

60 km/h

50 km/h

None

A bus travelling the first one-third distance at a speed of 10 km/h, the next one-third at 20 km/h and at last one-third at 60 km/h. The average speed of the bus is

9 km/ h

38 km/h

48 km/h

18 km/h

None

A car moves from $X$ to $Y$ with a uniform speed $\nu_{u}$ and returns to $X$ with a uniform speed $\nu_d.$ The average speed for this round trip is (2007)

$\sqrt {\nu _u\nu _d}$

$\frac {2\nu _d\nu _u}{\nu _d+ \nu _u}$

$\frac {\nu _u+ \nu _d}2$

$\frac {\nu _d\nu _u}{\nu _d+ \nu _u}$

None

A car runs at a constant speed on a circular track of radius 100 m, taking 62.8 seconds for every circular lap. The average velocity and average speed for each circular lap respectively is

10 m/s,0

10m/s, 10 m/s

0,0

0, 10m/s

None

A car moves a distance of 200 m. It covers the first half of the distance at speed 40 km/h and the second half of distance at speed $\nu$. The average speed is 48 km/h. The value of $\nu$ is

50 km/h

48 km/h

60 km/h

56 km/h

None