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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 22 July 2021, Shift 2, Physics Q15

Question 15 of 90 in this shift, Physics question 15 of 30, Section A.

A bullet of ‘4 g’ mass is fired from a gun of mass 4 kg. If the bullet moves with the muzzle speed of 50 ms−150\ \mathrm{ms^{-1}}, the impulse imparted to the gun and velocity of recoil of gun are :
  1. (1)0.4 kg ms−1, 0.1 ms−10.4\ \mathrm{kg\,ms^{-1}},\ 0.1\ \mathrm{ms^{-1}}
  2. (2)0.2 kg ms−1, 0.1 ms−10.2\ \mathrm{kg\,ms^{-1}},\ 0.1\ \mathrm{ms^{-1}}
  3. (3)0.2 kg ms−1, 0.05 ms−10.2\ \mathrm{kg\,ms^{-1}},\ 0.05\ \mathrm{ms^{-1}}Official answer
  4. (4)0.4 kg ms−1, 0.05 ms−10.4\ \mathrm{kg\,ms^{-1}},\ 0.05\ \mathrm{ms^{-1}}

Official answer

Option 3

NTA final key.

Chapter
Laws of Motion
Topic
Collisions
Idea tested
Momentum in Explosions

Same idea in other shifts

Asked 7× in all
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  2. 31 Jan 2024, Shift 1 · Q35An artillery piece of mass M1M_1 fires a shell of mass M2M_2 horizontally. Instantaneously after the firing, the ratio of kinetic energy…EasySingle correct
  3. 30 Jul 2022, Shift 2 · Q29A body moving horizontally on a smooth surface with a speed of 20 ms−1^{-1} splits into two parts and continue to move in the same…MediumNumerical value
  4. 29 Jun 2022, Shift 1 · Q32A body of mass M at rest explodes into three pieces, in the ratio of masses 1:1:21 : 1 : 2. Two smaller pieces fly off perpendicular to each…EasySingle correct
  5. 31 Aug 2021, Shift 2 · Q8A block moving horizontally on a smooth surface with a speed of 4040 m/s splits into two parts with masses in the ratio of 1:21:2. If the…MediumSingle correct
  6. 18 Mar 2021, Shift 1 · Q22A ball of mass 10 kg moving with a velocity 10310\sqrt{3} m/s along the xx-axis, hits another ball of mass 20 kg which is at rest. After…MediumNumerical valueHas a figure

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.