IIT JEE MCQ Quiz Hub

IIT JEE Circular Motion Centre Of Mass

Choose a topic to test your knowledge and improve your IIT JEE skills

1. A wheel is at rest. Its angular velocity increases uniformly and becomes 80 rad/s after 5s. The total angular displacement is:




2. A national roadway bridge over a canal is in the form of an arc of a circle of radius 49 m. What is the maximum speed with which a car can move without leaving the ground at the highest point? (Take g = 9.8 m/second square)




3. A car of 1400 kg is moving on a circular path of radius 30 m with a speed of 40 km/h. When the driver applies the brakes and the car continues to move along the circular path, what is the maximum deceleration possible if the tyres are limited to a total horizontal friction of 10.6 kN?




4. A heavy stone hanging from a massless string of length 15 m is projected horizontally with speed 147 m/s. The speed of the particle at the point where the tension in the string equals the weight of the particle is:




5. A car travels with a uniform velocity in north direction. It goes over a piece of mud which sticks to the tyre, the particles of the mud, as it leaves the ground are thrown:




6. A curved section of a rod is banked for a speed v. If there is no friction between road and tyres of the car, than:




7. A motor cyclist rides around the well with a round vertical wall and does not fall down while riding because:




8. A projectile is projected at an angle 60 degree with horizontal with speed 10 m/s. The minimum radius of curvature of the trajectory described by the projectile is:




9. A particle of mass 100 g tied to a string is rotated along a circle of radius 0.5 m. The breaking tension of string is 10N. The maximum speed with which particle can be rotated without breaking the string is:




10. When a body moves with constant speed in a circular path, then:




11. A stone of mass 0.3 kg attached to a 1.5 m long string is whirled around in a horizontal circle at a speed of 6 m/s. The tension in the string is:




12. Which of the following statements is false for a particle moving in a circle with a constant angular speed?




13. Which of the following statements about the centripetal and centrifugal forces is correct?




14. The string of a pendulum is horizontal. The mass of bob attached to it is m. Now the string is released. The tension in the string in the lowest position, is:




15. Let ? denote the angular displacement of a simple pendulum oscillating in a vertical plane If the mass of the bob is m, the tension in the string is mg cos ?:




16. A stone of mass 1 kg is tied at one end of string of length 1m It is whirled in a vertical circle at constant speed of 4 m/s The tension in the string is 6N when the stone is at: (g = 10 m/second square)




17. The speed of a particle moving in a circle is increasing. The dot product of its acceleration and velocity is:




18. A car moving on a horizontal road may be thrown out of the road in taking a turn:




19. A small body of mass m slides down from the top of a hemisphere of radius R. The surface of block and hemisphere are frictionless. The height at which the body loses contact with the surface of the sphere is:




20. When a simple pendulum is rotated in a vertical plane with constant angular velocity, centripetal force is:




21. Mark correct option or options from the following




22. A stone of mass 1 kg is tied to the end of a string 1 m long It is whirled in a vertical circle The velocity of the stone at the bottom of the circle is just sufficient to take it to the top of circle without slackening of the string What is the tension in the string at the top of the circle? (Take g = 10 m/s)




23. A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion of the particle takes place in a plane. It follows that:




24. The maximum speed with which an automobile can round a curve of radius 8 m without slipping if the road is unbanked and the co-efficient of friction between the road and the tyres is 0.8, is: (g = 10 m/second square)




25. A stone of mass m tied to a string of length l is rotated in a circle with the other end of the string as the centre. The speed of the stone is v. If the string breaks, the stone will:




26. In circular motion:




27. A coin placed on a rotating turntable just slips if it is placed at a distance of 8 cm from the centre. If angular velocity of the turntable is doubled, it will just slip at a distance of:




28. A chain of 125 links is 125 m long and has a mass of 2 kg with the ends fastened together It is set for rotating at 50 rev/s, the centripetal force on each link is:




29. A body is rolling without slipping on a horizontal plane. The rotational energy of the body is 40% of the total kinetic energy. Identify the body.




30. he diameter of a flywheel increases by 1%. The percentage increase in moment of inertia about its axis passing through the centre will be




31. The angular momentum changes from 2 units to 6 units in 4 s. The torque is




32. A particle performs uniform circular motion with an angular momentum L. If the frequency of particle s motion is doubled and its kinetic energy is halved, then the angular momentum becomes




33. A mass m is moving with a constant velocity parallel to the x -axis. Its angular momentum w. r. t. the origin




34. A body crosses the topmost point of a vertical circle with critical speed. What will be its acceleration when the string is horizontal ?




35. A sphere is rolling without slipping on a horizontal plane. The ratio of its rotational kinetic energy and translational kinetic energy is




36. Which of the following is conserved when the torque acting on a system is zero ?




37. If the Earth shrinks to half of the present radius, without any change in mass, then the duration of day and night becomes




38. A body rolls down an inclined plane If its kinetic energy of rotational motion is 40% of its kinetic energy of translation, then the body is




39. Two wheels, each with four spokes, are mounted one behind the other and aligned such that an observer sees only four spokes At t =0 minute, one wheel begins to spin at 5 revolutions/ minute and the other at 4 revolutions / minute Upto t = 1 minute, how many times the observer would see only four spokes ?




40. A particle is projected so as to just move along a vertical circle. The ratio of the tensions in the string when the particle is at the lowest and highest point on the circle is




41. A rigid spherical body is spinning around an axis without any external torque Due to change in temperature, the volume increases by 1% The angular speed will approximately




42. When a sphere rolls without slipping the ratio of kinetic energy of translation to its total kinetic energy is




43. A coin placed on a rotating turntable just slips if it is placed at a distance of 4 cm from the center If the angular velocity of the turntable is doubled, it will just slip at a distance of




44. Radius of gyration of a body about an axis at a distance of 6 cm from its centre of mass is 10 cm, The radius of gyration about a parallel axis through its centre of mass is




45. If the angular momentum of a body increases by 50%, its kinetic energy of rotation increases by




46. A child stands at the centre of a turn table with his two arms outstretched. The turntable is set rotating with an angular speed of 40 rev/min. Now, the child folds his hands back and thereby reduces his moment of inertia to 2 / 5 times the initial value. The new kinetic energy of rotation. The value of x is




47. The moment of inertia of uniform circular disc about a diameter is I. Its moment of inertia about an axis perpendicular to its plane and passing through a point on its rim will be




48. The string of a pendulum is horizontal. The mass of the bob attached to it is m. Now the string is released. The tension in the string in the lowest position is




49. A coin placed on a gramophone record rotating at 33 r p m files off the record, if it is placed at a distance of more than 16 cm from the axis of rotation If the record is revolving at 66 r p m, the coin will fly off if it is placed at a distance not less than




50. The masses of two uniform discs are in the ratio 1 : 2 and their diameters in the 2 : 1 The ratio of their moments of inertia about the axes passing through their respective centres and perpendicular to their planes is




51. A nearly massless rod is pivoted at one end so that it can swing freely as a pendulum Two masses 2m and m are attached to it at distance b and 3b respectively from the pivot The rod is held horizontal and then released The angular acceleration of the rod at the instant it is released is




52. A chain of 125 links is 1.25 m long and has a mass of 2 kg. With the ends fastened together, it is set rotating at 3000 rev/ min. The centripetal force on each link is




53. A disc-like reel with massless thread unrolls itself while falling vertically downwards The acceleration of its fall is




54. Two solid spheres are made of the same material. The ratio of their diameters is 1 : 2. The ratio of their moments of inertia about their respective diameters is