Q.1
A body falling vertically downwards under gravity breaks in two unequal parts of unequal masses. the centre of mass of the two parts taken together shifts horizontally towards
  • a) lighter piece
  • b) heavier piece
  • c)depends on the vertical velocity at the time of breaking
  • d)does 't shift horizontally
Q.2
A sphere can not roll on
  • a) a smooth inclined surface
  • b) a smooth horizontal surface
  • c) a rough inclined surface
  • d) a rough horizontal surface
Q.3
Two racing cars of mass m1 and m2 are moving in circles of radii r1 and r2 respectively. Their speeds are such that each makes a complete circle in the same length of time t. The ratio of the angular speed of the first to the second car is [ M.N.R. 1995]
  • a)m1 : m2
  • b) r1 : r2
  • c)1:1
  • d)m1r1 : m2r2
Q.4
A ring and disc have the same mass and radius. The ratio of their moment of inertia about an axis is [ punjab CET 1995]
  • a) 1:1
  • b) 2:1
  • c)4:1
  • d)1:2
Q.5
A man is sitting with folded hands on a revolving table. Suddenly, he stretches his arms. Angular speed of the table would [ CPMT 1996]
  • a) increase
  • b) decrease
  • c)remain the same
  • d)nothing can be said
Q.6
When a body rolls down an inclined plane, its potential energy is converted into [ CBSE 1996]
  • a) translational K.E only
  • b) rotational K.E only
  • c) translational and rotational K.E
  • d) none of above
Q.7
A raw egg and a hard boiled egg are made to spin on a table with the same angular speed about the same axis. The ratio of the time taken by the two to stop is [ CPMT 1996]
  • a) =1
  • b) < 1
  • c) > 1
  • d) none of the above
Q.8
A couple produces a ... [ pre-medical dental, 1997]
  • a) pure linear motion
  • b) pure rotational motion
  • c) both linear and rotational motion
  • d) no motion
Q.9
If sphere is rolling , the ratio of the rotational energy to the total kinetic energy is given by [ MEE BHU 1997]
  • a) 7:10
  • b) 2:5
  • c) 10:7
  • d) 2:7
Q.10
The moment of inertia of a solid sphere and a spherical shell of equal masses about their diameters are equal. the ration of their radii are .. [ CBSE 1997]
  • a) 5:3
  • b) 3:5
  • c) √5 : √3
  • d) √3 : √5
Q.11
A body rolls down an inclined plane. If its kinetic energy of rotational motion is 40% of its kinetic energy of translational motion, then the body is a
  • a)ring
  • b) cylinder
  • c)spherical shell
  • d)solid sphere
Q.12
The least coefficient of friction for an inclined plane at an angle α with horizontal, in order that a solid cylinder will roll down it without slipping is [ CET 1997 punjab]
  • a) 2/3( tan α)
  • b) 2/7 (tan α)
  • c)1/3 (tanα)
  • d)4/3( tan α)
Q.13
A mass m is moving with a constant velocity along a line parallel to the x-axis away from the origin. Its angular momentum with respect to the origin. Its angular momentum with respect to the origin is [ IIT 1997]
  • a) zero
  • b) constant
  • c)goes on decreasing
  • d)goes on increasing
Q.14
Three identical metal balls each of radius r are placed touching each other on a horizontal surface such that an equilateral triangle is formed when such centres of three balls are joined. The centre of mass of system is located at [CBSEPMT 1995]
  • a) horizontal surface
  • b) centre of one of the balls
  • c) line joining centre of any two balls
  • d) point of intersection of medians
Q.15
The moment of inertia of disc of mass M and radius R about an axis, which is tangential to circumference of disc and parallel to its diameter [ CBSE PMT 1999]
  • a)(3/2) MR2
  • b) (2/5) MR2
  • c)(5/4) MR2
  • d)(4/4) MR2
Q.16
The radius of gyration of a uniform rod of length L about on axis passing through its centre of mass [AMU 1999]
  • a) L/ √12
  • b) L2 / 12
  • c)L/√3
  • d)L/√2
Q.17
A wheel is rotating at 900 r.p.m about its axis. When power is cut off it comes to rest in 1 minute. The angular retardation is rad/s2 [ MP CEE 1999]
  • a) π/2
  • b) π/4
  • c)π/6
  • d)π/8
Q.18
A solid cylinder rolls down a smooth inclined plane 4.8m high without slipping what is itslinear speed at the bottom of the plane, if it starts rolling from the top of the plane?(take g=10 m/s2)
  • a) 4 m/s
  • b) 2 m/s
  • c) 10 m/s
  • d) 8 m/s
Q.19
A cylindrical solid of mass M has radius R and length L. Its moment of inertia about a generator is [ MP PMT 2009]
  • a)
    ch-6_qn-113choice_img_no1.png
  • b)
    ch-6_qn-113choice_img_no2.png
  • c)½ MR2
  • d)(3/2) MR2
Q.20
An athlete throws a discus from rest to a final angular velocity of 15rad/s in 0.27s before releasing it. During acceleration, discuss moves in a circular arc of radius 0.81m. Acceleration of discuss before it is released is .... ms2 [ kerala PET 2004]
  • a)45
  • b) 182
  • c)187
  • d)192
Q.21
Three identical spheres, each of mass 1 kg are kept as shown in figure, touching each other, with their centre on a straight line. If their centre are marked P,Q,R respectively, the distance of centre of mass of the system from P is [ kerala C.E.T 2005]
ch-6_que_no-118_img_no1.png
  • a) (PQ + PR + QR) / 3
  • b) (PQ + PR) / 3
  • c)(PQ + QR) / 3
  • d)(PQ + QR + PR) / 3
Q.22
A solid cylinder of mass 20kg has length 1m and radius 0.2m. Then its moment of inertia in kgm2 about its geometrical axis is [ kerala PMT 2005]
  • a)0.8
  • b) 0.4
  • c)0.2
  • d)20.4
Q.23
A given shaped glass tube having uniform cross section is filed with water and is mounted on a rotating shaft as shown in figure. If the tube is rotated with constant angular velocity ω, then [ AIIMS 2005]
ch-6_que_no-120_img_no1.png
  • a) water levels in both section A and B goes up
  • b) water level in section A goes up and then in section B comes down
  • c) Water level in section A comes down and then in B goes up
  • d) water level remains the same in both the sections
Q.24
A constant torque is acting on a uniform circular wheel changes its angular momentum from A0 to 4A0 in 4 seconds. The magnitude of this torque is [ BHU 1998]
  • a)(3/4)A0
  • b) A0
  • c)4A0
  • d)12A0
Q.25
An inclined plane makes an angle of 30° with the horizontal. A solid sphere rolling down this inclined plane from rest without slipping has a linear acceleration equal to [ MPPMT 1987]
  • a) g/3
  • b) 2g/3
  • c)5g/7
  • d)5g/14
Q.26
The moment of inertia of a circular ring about an axis passing through its centre and normal to its plane passing through its centre and normal to its plane is 200gm/cmThen its moment of inertia about a diameter is [ MPPMT 1987]
  • a) 40 gm cm2
  • b) 300 gm cm2
  • c)200 gm cm2
  • d)100 gm cm2
Q.27
Moment of momentum is called
  • a) torque
  • b) weight
  • ac) moment of inertia
  • d) angular momentum
Q.28
A dancer on ice spins faster when she folds her hand. This is due to [ CPMT 1986]
  • a)increase in energy and increase in angular momentum
  • b) decrease in friction at the skates
  • c)constant angular momentum and increase in kinetic energy
  • d)increase in energy and decrease in angular momentum
Q.29
The rotational K.E. of a body is E and its moment of inertia id I. The angular momentum is [ MPPMT 1993]
  • a) EI
  • b) 2 √(EI)
  • c) √(2EI)
  • d)E/I
Q.30
A homogeneous disc of mass 2kg and radius 15cm is rotating about its axis ( which is fixed) with an angular velocity of 4 radian/sec with an angular velocity of 4 radian/sec. The linear momentum of the disc is ..[ CPMT 1989]
  • a) 1.2 kg m/s
  • b) 1.0 kg m/s
  • c)0.6 kg m/s
  • d)none of the above
0 h : 0 m : 1 s