A cae is travelling along a straight line. It covers one-half of the total, distance with a velocity ` 10 km//h` . The remaining part of the distance was covered with velocity `12 ms^(-1)`. For half the time and with velocity ` 16 ms^(-1)` for the other half the tiem. Find the average speed over the whole time of motion.

Explanation

Let (S) be total distance to be travelled by car. The taken by car to cover the distance ` S //2 ` with velocity ` Then S/2 = 12 xx t-2 /2 + 16 xx t_2 /2 = 14 t-2`
or ` t_2 = S/928)`
Total time taken , `T= t_1 = t_2 = S/ ( 20) = S/( 28) = ( 12S)/( 140)` ltbRgt Average speed ` = S /T = S/ ( 12 S// 140)`
` = ( 140)/( 12) = 11. 6 ms^(-1)`.