Verified Solution • 2025–26 Session moderate

QNEET-2016-Ph-1143: NEET 2016 Physics - Class 11 NEET-2016-Ph-1143 Solution: Two cars P and Q start from a point at the same time in a…

Two cars P and Q start from a point at the same time in a straight line and their positions are represented by xP(t)=(at+bt2)x_P(t) = (at + bt^2) and xQ(t)=(ft−t2)x_Q(t) = (ft - t^2). At what time do the cars have the same velocity? a−f1+b\frac{a-f}{1+b} a+f2(b−1)\frac{a+f}{2(b-1)} a+f2(1+b)\frac{a+f}{2(1+b)} f−a2(1+b)\frac{f-a}{2(1+b)}

Multiple Choice Options

  • A a−f1+b{{a - f} \over {1 + b}} 1 + b a _ f _
  • B a+f2(b−1){{a + f} \over {2\left( {b - 1} \right)}} 2 ( b _ 1 ) a + f _
  • C a+f2(1+b){{a + f} \over {2\left( {1 + b} \right)}} 2 ( 1 + b ) a + f _
  • D f−a2(1+b){{f - a} \over {2\left( {1 + b} \right)}} 2 ( 1 + b ) f _ a _

Step-by-Step Verified Solution

For car P, x P (t) = (at + bt 2 ) v P (t) = d x p ( t ) d t = a + 2bt Similarly for car Q, x Q (t) = (ft - t 2 ) v Q (t) = d x Q ( t ) d t = f - 2t When they have same velocity then, v P (t) = v Q (t) _ a + 2bt = f - 2t _ 2t(b + 1) = f - a _ t = f _ a 2 ( 1 + b )

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