Q. A particle moving in a straight line covers half the distance with a speed of 3$ms^{- 1}$. The other half of the distance is covered in two equal time intervals with speeds of $4.5ms^{- 1}$and $7.5ms^{- 1}$. The average speed of the particle during this motion is
A) $4ms^{- 1}$
B) 5$ms^{- 1}$
C) 5.5$\ ms^{- 1}$
D) 4.8$\ ms^{- 1}$
Explanation
(a) Average speed for other half of distance
$= \frac{4.5 + 7.5}{2}ms^{- 1} = 6ms^{- 1}$
Average speed during whole motion
$= \frac{2 \times 3 \times 6}{3 + 6}ms^{- 1} = 4ms^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.