Kinematics

JEE Main level, single correct, medium

77 of 308

Question 77 of 308

A car, moving with a speed of 50 km/hr50 \mathrm{~km} / \mathrm{hr}, can be stopped by brakes after at least 6 m6 \mathrm{~m}. If the same car is moving at a speed of 100 km/hr100 \mathrm{~km} / \mathrm{hr}, the minimum stopping distance is

Show answer and solution

Answer: (C) 24 m24 \mathrm{~m}

Energy == Work done by force (F)(\mathrm{F})
⇒12 m.(50)2=(F)(6)⇒F=2500 m2×6\Rightarrow \frac{1}{2} \mathrm{~m} .(50)^2=(\mathrm{F})(6) \quad \Rightarrow \mathrm{F}=\frac{2500 \mathrm{~m}}{2 \times 6}
For v=100 km/hr12⋅m(100)2=(F)(S)\mathrm{v}=100 \mathrm{~km} / \mathrm{hr} \frac{1}{2} \cdot \mathrm{m}(100)^2=(\mathrm{F})(\mathrm{S})
⇒12 m(100)2=(2500 m2×6)S⇒S=100×100×6×22500×2=24 m\begin{aligned} & \Rightarrow \frac{1}{2} \mathrm{~m}(100)^2=\left(\frac{2500 \mathrm{~m}}{2 \times 6}\right) \mathrm{S} \\ & \Rightarrow \mathrm{S}=\frac{100 \times 100 \times 6 \times 2}{2500 \times 2}=24 \mathrm{~m} \end{aligned}

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.
See it move: Projectile motion simulationDrag the sliders and watch the numbers in this question change.Revise Kinematics & Projectile Motion firstFormula sheet, solved examples and the traps students fall into.

More Physics practice

JEE Main Physics practice question on Kinematics (Uniform Motion), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.