Practice Questions

Q5. A particle of mass 100 g is projected at time t = 0 with a speed 20 m s–1 at an angle 45° to the horizontal as given in the figure. The magnitude of the angular momentum of the particle about the starting point at time t = 2 s is found to be √K kg m2 s−1 . The value of K is ______. (Take g = 10 m s−2 )

Q5. The weight of a body at the surface of earth is 18 N. The weight of the body at an altitude of 3200 km above the earth's surface is (given, radius of earth 𝑅𝑒= 6400 km) (1) 9 . 8 N (2) 4 . 9 N (3) 19 . 6 N (4) 8 N

Q5. A body of mass 5 kg is moving with a momentum of 10 kg m s−1 . Now a force of 2 N acts on the body in the direction of its motion for 5 s. The increase in the Kinetic energy of the body is _____ J.

Q5. A nucleus disintegrates into two smaller parts, which have their velocities in the ratio 3 : 2 . The ratio of their 1 nuclear sizes will be ( x3 ) 3 . The value of ‘ x’ is:

Q5. To maintain a speed of 80 km h−1 by a bus of mass 500 kg on a plane rough road for 4 km distance, the work done by the engine of the bus will be _____ kJ. [The coefficient of friction between tyre of bus and road is 0. 04 ]

Q5. A force F = (5 + 3y2) acts on a particle in the y-direction, where F is newton and y is in meter. The work done by the force during a displacement from y = 2 m to y = 5 m is ______ J .

Q6. A body of mass 1 kg collides head on elastically with a stationary body of mass 3 kg. After collision, the smaller body reverses its direction of motion and moves with a speed of 2 m s−1 . The initial speed of the smaller body before collision is ______ m s−1 . JEE Main 2023 (25 Jan Shift 2) JEE Main Previous Year Paper

Q6. For rolling spherical shell, the ratio of rotational kinetic energy and total kinetic energy is x . The value of x is 5 _____.

Q6. A uniform solid cylinder with radius R and length L has moment of inertia I1 , about the axis of cylinder. A concentric solid cylinder of radius R′ = R2 and length L′ = L2 is carved out of the original cylinder. If I2 is the moment of inertia of the carved out portion of the cylinder then I1 = __________. I2 (Both I1 and I2 are about the axis of the cylinder)

Q6. A 100 m long wire having cross-sectional area 6 . 25 × 10-4 m2 and Young's modulus is 1010 N m-2 is subjected to a load of 250 N, then the elongation in the wire will be : (1) 6 . 25 × 10-3 m (2) 4 × 10-4 m (3) 6 . 25 × 10-6 m (4) 4 × 10-3 m Q7. 1 g of a liquid is converted to vapour at 3 × 105 Pa pressure. If 10% of the heat supplied is used for increasing the volume by 1600 cm3 during this phase change, then the increase in internal energy in the process will be : (1) 4320 J (2) 432000 J (3) 4800 J (4) 4 . 32 × 108 J JEE Main 2023 (24 Jan Shift 1) JEE Main Previous Year Paper

Q6. A 0. 4 kg mass takes 8 s to reach ground when dropped from a certain height P above surface of earth. The loss of potential energy in the last second of fall is ______ J. [Take g = 10 m s−2 ]

Q6. A ring and a solid sphere rotating about an axis passing through their centres have same radii of gyration. The axis of rotation is perpendicular to plane of ring. The ratio of radius of ring to that of sphere is . The value √2x of x is _____.

Q6. A hollow spherical ball of uniform density rolls up a curved surface with an initial velocity 3 m s−1 (as shown in figure). Maximum height with respect to the initial position covered by it will be _____ cm (take, g = 10 m s−2 ) JEE Main 2023 (08 Apr Shift 2) JEE Main Previous Year Paper

Q6. A nucleus disintegrates into two nuclear parts, in such a way that ratio of their nuclear sizes is 1 : 21/3 . Their respective speed have a ratio of n : 1 . The value of n is_________

Q6. A body of mass 2 kg is initially at rest. It starts moving unidirectionally under the influence of a source of constant power P . Its displacement in 4 s is 31 α2√P m. The value of α will be ______. JEE Main 2023 (30 Jan Shift 2) JEE Main Previous Year Paper

Q6. A ball is dropped from a height of 20 m. If the coefficient of restitution for the collision between ball and floor is 0. 5 , after hitting the floor, the ball rebounds to a height of ______ m.

Q6. The momentum of a body is increased by 50% . The percentage increase in the kinetic energy of the body is_ _______%.

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. 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 ______.

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. 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. 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. 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