A train starting from rest first accelerates uniformly up to a speed of for time t, then it moves with a constant speed for time 3t. The average speed of the train for this duration of journey will be (in ) :
- (A)80
- (B)70✓ Correct
- (C)30
- (D)40
Answer: (B)
Solution
First phase (uniform acceleration from rest to km/h in time ): distance .
Second phase (constant km/h for ): distance .
Second phase (constant km/h for ): distance .
JEE Main · 2024 · 06 Apr 2024 · Shift 1 · Single correct option