On a 60 km straight road, a bus travels the first 30 km with a uniform

1.	On a 60 km straight road, a bus travels the first 30 km with a uniform speed of 30 kmh-1 . How fast must the bust travel the next 30 km so as to have average speed of 40 kmh-1 for the entire trip?
Answer» Average Velocity = \(\frac{s_1+s_2}{t_1+t_2}=\frac{2\times v_1v_2}{v_1+v_2}\) 40 km/hr = \(\frac{2\times30\frac{km}{hr}\times v_2}{30\frac{km}{hr}+v_2}\) 2 = \(\frac{3v_2}{30\frac{km}{hr}+v_2}\) 60 km/hr +2v₂ = 3v₂ v₂ = 60 km/hr

On a 60 km straight road, a bus travels the first 30 km with a uniform speed of 30 kmh-1 . How fast must the bust travel the next 30 km so as to have average speed of 40 kmh-1 for the entire trip?

Answer»

Average Velocity = \(\frac{s_1+s_2}{t_1+t_2}=\frac{2\times v_1v_2}{v_1+v_2}\)

40 km/hr = \(\frac{2\times30\frac{km}{hr}\times v_2}{30\frac{km}{hr}+v_2}\)

2 = \(\frac{3v_2}{30\frac{km}{hr}+v_2}\)

60 km/hr +2v₂ = 3v₂

v₂ = 60 km/hr