A particle moving in a straight line covers half the distance with speed 6 m/s. The other half is covered in two equal time intervals with speeds 9 m/s and 15 m/s respectively. The average speed of the particle during the motion is:
(A)8.8 m/s
(B)10 m/s
(C)9.2 m/s
(D)8 m/s✓ Correct
Answer: (D)
Solution
First half-distance S at 6 m/s takes t1=S/6. Second half is two equal times t: distance =9t+15t=24t=S⇒t=S/24. Average speed =t1+2t2S=S/6+S/122S=S/42S=8 m/s. Option (4).
JEE Main · 2024 · 09 Apr 2024 · Shift 1 · Single correct option