Cars A and B start from rest, accelerate uniformly at 4 m/s² and 1 m/s², and finish the same distance. A finishes 4 s earlier. Find the difference in their finishing speeds (m/s).
Physics · Mixed Chapter
JEE Main Practice

Question

Cars A and B start from rest, accelerate uniformly at 4 m/s² and 1 m/s², and finish the same distance. A finishes 4 s earlier. Find the difference in their finishing speeds (m/s).

G1 Physics · Accepted Answer

Step 1: Let A's time be t and B's time be t+4. Step 2: Equal distances imply ½(4)t² = ½(1)(t+4)². Step 3: Positive root: 2t = t+4 ⇒ t = 4 s. Then B takes 8 s. Step 4: v_A = 4×4 = 16 m/s; v_B = 1×8 = 8 m/s. Difference = 8 m/s.