Practice Test

Q1) Which of the following physical quantities is different from others ? Show Answer

Q2) SI units of moment of inertia are Show Answer

Q3) The dimensional formula for moment of inertia is Show Answer

Q4) Moment of inertia of a solid sphere about its diameter is (symbols have their usual meanings) Show Answer

Q5) The dimensional formula of angular acceleration is Show Answer

Q6) SI units of angular momentum are Show Answer

Q7) The dimensions of torque are Show Answer

Q8) The ratio of SI units to c.g.s. units of torque is Show Answer

Q9) Moment of inertia of a circular ring (mass m and radius r) about an axis passing through its centre of gravity and perpendicular to its plane is Show Answer

Q10) Radius of gyration is a scalar quantity measured in Show Answer

Q11) The ratio of SI units to c.g.s. units of angular momentum is Show Answer

Q12) A body of mass m tied to a string is moved in a vertical circle of radius r. The difference in tensions at the lowest point and the highest point is Show Answer

Q13) A car takes a turn around a circular curve. If it turns at double the speed,the tendency to overturn is Show Answer

Q14) The solar system is an example of Show Answer

Q15) Kinetic energy of rotation is measured in Show Answer

Q16) If the radius of the circular path of particle going around the circle is doubled without changing its frequency of rotation, then centripetal force on it is Show Answer

Q17) What happens to the centripetal acceleration of a particle, when its speed is doubled and angular velocity is halved ? Show Answer

Q18) For a particle moving along a circular path with a constant speed, the acceleration is constant in Show Answer

Q19) SI units of angular acceleration are Show Answer

Q20) Two satellites are going around the earth at a height of 250 km and 450 km respectively. If angular speed for both is same, then centripetal acceleration will be Show Answer

Q21) What is the minimum speed of a bike at the highest point of a globe of diameter 19.6 m ? Show Answer

Q22) A motor cyclist loops the loop whose diameter is 12 m. From what minimum height must he start in order to roll down and go around the loop ? Show Answer

Q23) The centre of mass of a rigid body may lie Show Answer

Q24) The unit of position vector of centre of mass is Show Answer

Q25) Two identical balls each of radius 20 cm are placed touching each other. Then the distance of their centre of mass from the point of contact is Show Answer

Q26) A shell at rest explodes. The centre of mass of the fragments Show Answer

Q27) A shell following a parabolic path explodes somewhere in its flight. The centre of mass of fragments will continue to move in Show Answer

Q28) A system comprises three particles, each of mass M and located at (1,1), (2,2) and (3,3). Then the co-ordinates of the centre of mass are Show Answer

Q29) Two particles P and Q initially at rest move towards each other under a mutual force of attraction. At the instant when velocity of P is v and that of Q is 2v, the velocity of centre of mass of the system is Show Answer

Q30) The sum of moments of masses of all the particles in a system about the centre of mass is always Show Answer

Q31) The motion of the centre of mass depends on Show Answer

Q32) The centre of mass of two particles lies on the line Show Answer

Q33) The position of centre of mass of a system of particles does not depend upon Show Answer

Q34) The moment of inertia of a body depends on its Show Answer

Q35) Radius of gyration of a body is independent of its Show Answer

Q36) The reduced mass of the system of two particles of masses m and 2m will be Show Answer

Q37) If the position of axis of rotation of a body is changed, which of the following quantities will change ? Show Answer

Q38) Which of the following plays the same role in rotational motion as it played by the mass in translatory motion ? Show Answer

Q39) The diameter of a flywheel is increased by 2%. Then increase in its moment of inertia about the central axis is Show Answer

Q40) Moment of inertia of a solid sphere about an axis tangential to its surface is (symbols have their usual meanings) Show Answer

Q41) Before jumping into water from above, a swimmer bends his body to Show Answer

Q42) Assertion:
The centre of mass of a body may lie where there is no mass.
Reason :
The centre of mass of a body is a point, where the whole mass of the body is supposed to be concentrated. Show Answer

Q43) Assertion :
Moment of inertia of a body is same, whatever be the axis of rotation.
Reason :
Moment of inertia depends on mass and size of the body. Show Answer

Q44) Assertion :
Power associated with torque is product of torque and angular speed of the body about the axis of rotation.
Reason :
It is rotational analogue of power in translatory motion. Show Answer

Q45) In order to rotate a bar pivoted at its mid point, we need to apply : Show Answer

Q46) A body is acted upon by two unequal forces in opposite directions, but not in one line. The effect is that : Show Answer

Q47) When a boy weighing 20 kgf sits at one end of a 4 m long see-saw, it gets depressed at this end. It can be brought to the horizontal position if a man weighing 40 kgf sits at : Show Answer

Q48) The moment of a force about a given axis depends : Show Answer

Q49) The unit of moment of force is : Show Answer

Q50) Which of the following is not the force at a distance : Show Answer

Q51) Relationship between kgf and N is : Show Answer

Q52) Which of the following appliances works on the principle of moments : Show Answer

Q53) SI unit of couple is Show Answer

Q54) The moment of the forces about O is Show Answer

Q55) Which of the following is different from others, as regards the centre of gravity ? Show Answer

Q56) Which of the following is different from others, as regards the centre of gravity ? Show Answer

Q57) For a particle moving along a circular path with a constant speed, the acceleration is constant in Show Answer

Q58) A body moves along a circular path of constant radius. The magnitude of its acceleration is Show Answer

Q59) A couple produces Show Answer

Q60) A rigid body is rotating about an axis. To stop the rotation, we have to apply Show Answer

Q61) The product of force and perpendicular distance from axis of rotation, is commonly called Show Answer

Q62) SI unit of couple is Show Answer

Q63) What is the conserved when no external torque acts on a system ? Show Answer

Q64) A constant torque acting on a uniform circular wheel changes its angular momentum from A to 4A in 4 seconds. The magnitude of the torque is Show Answer

Q65) A person standing on a rotating platform with his hands lowered out stretches his arms. The angular momentum of the person Show Answer

Q66) A body is moving with constant velocity parallel to x-axis. its angular momentum with respect to the origin will Show Answer

Q67) An engine develops 100 kW when rotating at 1800 rpm. Torque required to deliver the power is Show Answer

Q68) When sand is poured on a rotating disc, its angular velocity will Show Answer

Q69) Before jumping in water from above, a swimmer bends his body to Show Answer

Q70) A sphere is suspended by a thread of length L. The minimum horizontal velocity which has to be imparted to the sphere for it to reach the height of suspension is Show Answer

Q71) Which of the following wrongly represents the position of centre of gravity of the given objects ? Show Answer

Q72) Which of the following wrongly represents the position of centrre of gravity of the given objects ? Show Answer

Q73) For a constant mass, the graph between moment of inertia (I) and radius of gyration (K) is given Show Answer

Q74) Refer to Question 20 above, the graph between log I and log K is given by Show Answer

Q75) The figure below shows the position of centre of gravity by the point G for a circular ring, circular disc, rectangle and a parallelogram. Which one is different from other ? Show Answer