Question

a particle moving n a straight line covers half the distance with a speed of 3m/s . the other half of the distance is covered in 2 equal intervals of time with speeds o 4.5 n 7.5 m/s res^ly. find av. speed.

Answer 1

Heya,

let total distance of path is S ...
 

for first half , time taken if t

speed = distance/time

3 = S/2t

t = S/6      .............[1]

 

for second half , time taken is T ...

for first  T/2 it moves with 4.5

speed = distance/time

4.5 = 2x/T

 x = 4.5T/2   ...........[2]

for second T/2 it moves with 7.5

7.5 = 2y/T

y = 7.5T/2       ..........[3]

we have , x+y = S/2so

(7.5+4.5)T = S/2

T = S/24        ...............[4]

total time taken during its motion is T+t

 T(total) = T+t = S/24+S/6 = 5S/24

total distance = S

average speed = total distance/total time = S/

5S/24 = 24/5 = 【4.8m/s】ANSWER...

HOPE IT HELPS:-))