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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 26 August 2021, Shift 1, Physics Q16

Question 16 of 90 in this shift, Physics question 16 of 30, Section A.

The initial mass of a rocket is 1000 kg. Calculate at what rate the fuel should be burnt so that the rocket is given an acceleration of 20 ms−220\ \mathrm{ms^{-2}}. The gases come out at a relative speed of 500 ms−1500\ \mathrm{ms^{-1}} with respect to the rocket : [Use g=10 m/s2g=10\ \mathrm{m/s^2}]
  1. (1)60 kg s−160\ \mathrm{kg\ s^{-1}}Official answer
  2. (2)6.0×102 kg s−16.0\times10^{2}\ \mathrm{kg\ s^{-1}}
  3. (3)500 kg s−1500\ \mathrm{kg\ s^{-1}}
  4. (4)10 kg s−110\ \mathrm{kg\ s^{-1}}

Official answer

Option 1

NTA final key.

Chapter
System of Particles and Rotational Motion
Topic
Newton's Laws of Motion
Idea tested
Rocket Propulsion Thrust

Same topic in other shifts

All Newton's Laws of Motion questions
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  6. 7 Apr 2025, Shift 2 · Q28An object with mass 500 g moves along xx-axis with speed v=4xv=4\sqrt{x} m/s. The force acting on the object is :MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.