Mathematics in Physics

JEE Main level, single correct, medium

32 of 121

Question 32 of 121

Ship AA is sailing towards north-east with velocity) v⃗=30i^+50j^kmh−1\vec{v}=30\hat{i}+50\hat{j}km{h}^{-1} where i^\hat{i} points east and j^,\hat{j}, north. The ship BB is at a distance of 80km80km east and 150km150km north of Ship AA and is sailing towards the west at 10kmh−1.10km{h}^{-1}. AA will be at the minimum distance from BB in:

Show answer and solution

Answer: (C) 2.6h2.6h

v⃗rel=v⃗1−v2=40i+50j{\vec{v}}_{rel}={\vec{v}}_{1}-{v}_{2}=40i+50j
r⃗rel=r⃗1−r⃗2=−80i−150j{\vec{r}}_{rel}={\vec{r}}_{1}-{\vec{r}}_{2}=-80i-150j
tmin=∣v⃗rel⋅r⃗rel∣v⃗rel∣2∣=∣−3200−7500((40)2+(50)2)2∣{t}_{min}=\left|\dfrac{{\vec{v}}_{rel}\cdot {\vec{r}}_{rel}}{{\left|{\vec{v}}_{rel}\right|}^{2}}\right|=\left|\dfrac{-3200-7500}{{\left(\sqrt{{\left(40\right)}^{2}+{\left(50\right)}^{2}}\right)}^{2}}\right|
tmin=107004100=10741=2.6h{t}_{min}=\dfrac{10700}{4100}=\dfrac{107}{41}=2.6 h

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.

More Physics practice

JEE Main Physics practice question on Mathematics in Physics (Addition and Subtraction of Vectors), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.