Practice Questions

Q7. A machine gun of mass 10 kg fires 20 g bullets at the rate of 180 bullets per minute with a speed of 100 m s–1 each. The recoil velocity of the gun is : (1) 0. 02 m s−1 (2) 2. 5 m s−1 (3) 1. 5 m s−1 (4) 0. 6 m s−1

Q7. If 1000 droplets of water of surface tension 0 . 07 N m-1. having same radius 1 mm each, combine to from a single drop. In the process the released surface energy is- 22 Take π = 7 JEE Main 2023 (31 Jan Shift 1) JEE Main Previous Year Paper (1) 7 . 92 × 10-6 J (2) 7 . 92 × 10-4 J (3) 9 . 68 × 10-4 J (4) 8 . 8 × 10-5J

Q7. Given below are two statements: JEE Main 2023 (10 Apr Shift 1) JEE Main Previous Year Paper Statement I: Pressure in a reservoir of water is same at all points at the same level of water. Statement II: The pressure applied to enclosed water is transmitted in all directions equally. In the light of the above statements, choose the correct answer from the options given below: (1) Both Statement I and Statement II are false (2) Statement I is true but Statement II is false (3) Statement I is false but Statement II is true (4) Both Statement I and Statement II are true

Q7. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Earth has atmosphere whereas moon doesn’t have any atmosphere. Reason R: The escape velocity on moon is very small as compared to that on earth. In the light of the above statements, choose the correct answer from the options given below: JEE Main 2023 (06 Apr Shift 1) JEE Main Previous Year Paper (1) Both 𝐴 and 𝑅 are correct but 𝑅 is NOT the correct (2) 𝐴 is false but 𝑅 is true explanation of 𝐴 (3) Both 𝐴 and 𝑅 are correct and 𝑅 is the correct (4) 𝐴 is true but 𝑅 is false explanation of 𝐴

Q7. A circular plate is rotating in horizontal plane, about an axis passing through its centre and perpendicular to the plate, with an angular velocity ω. A person sits at the centre having two dumbbells in his hands. When he stretched out his hands, the moment of inertia of the system becomes triple. If E be the initial Kinetic energy of the system, then final Kinetic energy will be E . The value of x is x

Q7. A gas is compressed adiabatically, which one of the following statement is NOT true? (1) There is no heat supplied to the system (2) There is no change in the internal energy (3) The temperature of the gas increases (4) The change in the internal energy is equal to the work done on the gas

Q7. A wire of length L and radius r is clamped rigidly at one end. When the other end of the wire is pulled by a force f , its length increases by l. Another wire of same material of length 2L and radius 2r is pulled by a force 2f . Then the increase in its length will be: (1) 4l (2) 2l (3) 2l (4) l

Q7. On a temperature scale '𝑋', the boiling point of water is 65°X and the freezing point is -15°X. Assuming that the 𝑋 scale is linear. The equivalent temperature corresponding to -95°X on the Fahrenheit scale would be (1) -112°F (2) -48°F (3) -148°F (4) -63°F

Q7. The moment of inertia of a semicircular ring about an axis, passing through the center and perpendicular to the plane of ring, is 1 MR2 , where R is the radius and M is the mass of the semicircular ring. The value of x will x be _______ .

Q7. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : A spherical body of radius ( 5 ± 0 . 1 ) mm having a particular density is falling through a liquid of constant density. The percentage error in the calculation of its terminal velocity is 4%. Reason R : The terminal velocity of the spherical body falling through the liquid is inversely proportional to its radius. In the light of the above statements, choose the correct answer from the options given below (1) Both A and R are true and R is the correct (2) Both A and R are true but R is NOT the correct explanation of A explanation of A (3) A is true but R is false (4) A is false but R is true

Q7. Given below are two statements: Statement I: Acceleration due to earth's gravity decreases as you go 'up' or 'down' from earth's surface. JEE Main 2023 (24 Jan Shift 2) JEE Main Previous Year Paper Statement II: Acceleration due to earth's gravity is same at a height ' h' and depth ' d' from earth's surface, if h = d. In the light of above statements, choose the most appropriate answer form the options given below (1) Statement I is incorrect but statement II is correct (2) Both Statement I and Statement II are incorrect (3) Statement I is correct but statement II is incorrect (4) Both Statement I and II are correct

Q7. A solid sphere is rolling on a horizontal plane without slipping. If the ratio of angular momentum about axis of rotation of the sphere to the total energy of moving sphere is π : 22 then, the value of its angular speed will be _________rad s−1. JEE Main 2023 (13 Apr Shift 1) JEE Main Previous Year Paper

Q7. The orbital angular momentum of a satellite is L, when it is revolving in a circular orbit at height h from earth surface. If the distance of satellite from the earth centre is increased by eight times to its initial value, then the new angular momentum will be (1) 8 L (2) 9 L (3) 4 L (4) 3 L

Q7. Moment of inertia of a disc of mass M and radius ' R' about any of its diameter is MR2 . The moment of inertia 4 of this disc about an axis normal to the disc and passing through a point on its edge will be, x MR2 . The value 2 of x is ______.

Q7. Two satellites A and B move round the earth in the same orbit. The mass of A is twice the mass of B. The quantity which is same for the two satellites will be (1) Speed (2) Kinetic energy (3) Total energy (4) Potential energy

Q7. Choose the correct relationship between Poisson ratio 𝜎, bulk modulus ( 𝐾) and modulus of rigidity 𝜂 of a given solid object: (1) 𝜎= 3𝐾- 2𝜂 (2) 𝜎= 6𝐾+ 2𝜂 6𝐾+ 2𝜂 3𝐾- 2𝜂 3𝐾+ 2𝜂 6𝐾- 2𝜂 (3) 𝜎= (4) 𝜎= 6𝐾+ 2𝜂 3𝐾- 2𝜂

Q7. A mercury drop of radius 10 – 3 m is broken into 125 equal size droplets. Surface tension of mercury is 0 . 45 N m – 1 . The gain in surface energy is: (1) 2 . 26 × 10 – 5 J (2) 28 × 10 – 5 J (3) 17 . 5 × 10 – 5 J (4) 5 × 10 – 5 J JEE Main 2023 (01 Feb Shift 1) JEE Main Previous Year Paper

Q7. If a solid sphere of mass 5 kg and a disc of mass 4 kg have the same radius, then the ratio of moment of inertia of the disc about a tangent in its plane to the moment of inertia of the sphere about its tangent will be x . The 7 value of x is ______.

Q7. A solid sphere of mass 2 kg is making pure rolling on a horizontal surface with kinetic energy 2240 J. The velocity of centre of mass of the sphere will be ______ m s−1 .

Q7. Two discs of same mass and different radii are made of different materials such that their thicknesses are 1 cm and 0. 5 cm respectively. The densities of materials are in the ratio 3 : 5 . The moment of inertia of these discs respectively about their diameters will be in the ratio of x . The value of x is ______. 6

Q7. Force acts for 20 s on a body of mass 20 kg , starting from rest, after which the force ceases and then body describes 50 m in the next 10 s . The value of force will be : JEE Main 2023 (29 Jan Shift 2) JEE Main Previous Year Paper (1) 40 N (2) 5 N (3) 20 N (4) 10 N

Q7. ICM is moment of inertia of a circular disc about an axis (CM) passing through its center and perpendicular to the plane of disc. IAB is its moment of inertia about an axis AB perpendicular to plane and parallel to axis CM at a distance 2 R from center, where R is the radius of the disc. The ratio of IAB and ICM is x : 9. The value of x is 3 ______.

Q8. The pressure of a gas changes linearly with volume from 𝐴 to 𝐵 as shown in figure. If no heat is supplied to or extracted from the gas then change in the internal energy of the gas will be (1) 6 J (2) Zero (3) -4 . 5 J (4) 4 . 5 J 𝐶𝑃

Q8. Consider two containers 𝐴 and 𝐵 containing monoatomic gases at the same Pressure 𝑃, Volume 𝑉 and 1 Temperature 𝑇. The gas in 𝐴 is compressed isothermally to of its original volume while the gas in 𝐵 is 8 compressed adiabatically to 1 of its original volume. The ratio of final pressure of gas in 𝐵 to that of gas in 𝐴 is 8 (1) 8 (2) 4 3 1 (3) (4) 8 2 8

Q8. Two particles of equal mass m move in a circle of radius r under the action of their mutual gravitational attraction. The speed of each particle will be : (1) √Gm2r (2) √4Gmr (3) √Gmr (4) √Gm4r