Question

A particle moving in a straight line covers half the distance
with speed of 3m/s. The other half of the distance covered
in two equal time intervals with speed of 4.5 m/s
7.5 m/s respectively. The average speed of the particle
during this motion is
(a) 4.0 m/s
(b) 5.0 m/s
(c) 5.5 m/s
(d) 4.8 m/s​

Answer 1

Answer:

I think it's 4.8. hopes that it helps u

Answer 2

Answer:

4.0 m/s

Explanation:

avg. speed while covering the 2nd half

= (4.5+7.5)/2 = 6m/s

average speed of the particle during this motion = 2 × 3 × 6/ (3+6)

= 36/9 = 4 m/s

option (a) is correct

Or

let total dis. be = 48 m

time taken at 3 m/s = 24/3 = 8s

time taken to cover 2nd half

= 4.5×t + 7.5 × t = 24

12t = 24 => t = 2sec

total time taken in 2nd half

= 2t = 2(2) = 4seconds

average speed = total distance/total time taken

= 48/(8+4) = 48/12 = 4m/s Answer