Practice Questions

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. Two planets A and B of radii 𝑅 and 1 . 5 𝑅 have densities 𝜌 and 𝜌 respectively. The ratio of acceleration due to 2 gravity at the surface of B to A is: (1) 2 : 3 (2) 2 : 1 (3) 3 : 4 (4) 4 : 3

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. An object of mass m initially at rest on a smooth horizontal plane starts moving under the action of force F = 2 N . In the process of its linear motion, the angle θ (as shown in figure) between the direction of force and horizontal varies as θ = kx , where k is a constant and x is the distance covered by the object from its initial position. The expression of kinetic energy of the object will be E = nk sin θ . The value of n is ______.

Q5. A body of mass 10 kg is moving with an initial speed of 20 m s−1 . The body stops after 5 s due to friction between body and the floor. The value of the coefficient of friction is: (Take acceleration due to gravity g = 10 m s−2 ) (1) 0. 2 (2) 0. 3 (3) 0. 5 (4) 0. 4

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 body is dropped on ground from a height h1 and after hitting the ground, it rebounds to a height h2 . If the ratio of velocities of the body just before and after hitting ground is 4 , then percentage loss in kinetic energy of the body is x . The value of x is _____. 4

Q5. A block of √3 kg is attached to a string whose other end is attached to the wall. An unknown force F is applied so that the string makes an angle of 30° with the wall. The tension T is : (Given g = 10 m s–2 ) (1) 20 N (2) 25 N (3) 10 N (4) 15 N

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 .

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. A block of mass m slides down the plane inclined at angle 30° with an acceleration 4g . The value of coefficient of kinetic friction will be : (1) 2√3+1 (2) 1 2 2√3 (3) √3 (4) 2√3−1 2 2

Q5. At a certain depth 𝑑 below surface of earth, value of acceleration due to gravity becomes four times that of its value at a height 3𝑅 above earth surface. Where 𝑅 is Radius of earth (Take 𝑅 = 6400 km). The depth 𝑑 is equal to (1) 5260 km (2) 640 km (3) 2560 km (4) 4800 km

Q5. Two satellites of masses m and 3 m revolve around the earth in circular orbits of radii r & 3r respectively. The ratio of orbital speeds of the satellites respectively is (1) √3: 1 (2) 3: 1 (3) 9: 1 (4) 1: 1

Q5. The time period of a satellite, revolving above earth's surface at a height equal to R will be (Given 𝑔= 𝜋2 m s-2, 𝑅= radius of earth) (1) √2R (2) √8R (3) √32R (4) √4R

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. An object of mass 8 kg is hanging from one end of a uniform rod CD of mass 2 kg and length 1 m pivoted at its end C on a vertical wall as shown in figure. It is supported by a cable AB such that the system is in equilibrium. The tension in the cable is: (Take g = 10 m s−2 ) JEE Main 2023 (25 Jan Shift 1) JEE Main Previous Year Paper (1) 240 N (2) 90 N (3) 300 N (4) 30 N

Q6. Two identical particles each of mass m go round a circle of radius a under the action of their mutual gravitational attraction. The angular speed of each particle will be : (1) √Gma3 (2) √Gm8a3 (3) √Gm4a3 (4) √Gm2a3

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 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_ _______%.

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. If the gravitational field in the space is given as - 𝑟2. Taking the reference point to be at 𝑟= 2 cm with gravitational potential 𝑉= 10 J kg-1. Find the gravitational potentials at 𝑟= 3 cm in SI unit (Given, that 𝐾= 6 J cm kg-1) (1) 9 (2) 11 (3) 12 (4) 10

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 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. A planet has double the mass of the earth. Its average density is equal to that of the earth. An object weighing 𝑊 on earth will weigh on that planet: (1) 1 (2) 1 2 4W 2 3W (3) 2W (4) 2 23W