A simple speed.

Classical Mechanics Level 1

A car moves on road AB in $\displaystyle t_1$ time with average speed $\displaystyle v_1=30 km/h$ .

Then it moves on road BC in $\displaystyle t_2$ time with average speed $\displaystyle v_2=20 km/h$ .

Calculate the average speed of the car in the entire road AC in $\displaystyle km/h$ , known that $\displaystyle t_1=t_2$

1 solution

Vishwak Srinivasan
Sep 10, 2015

Distance moved in $t_1 = v_1t_1 = 30t_1$

Distance moved in $t_2 = v_2t_2 = 20t_2$

Total distance moved in $t_1 + t_2 = 30t_1 + 20t_2$

Average Speed $<v> = \dfrac{30t_1 + 20t_2}{t_1 + t_2}$

When $t_1 = t_2$ , $<v> = \dfrac{30+20}{2} = 25 km/h$

All the variables are mixed up !! Please choose different variable !

Syed Baqir - 5 years, 9 months ago