Q.1
A wheel of radius 1m rolls forward half a revolution on a horizontal ground. The magnitude of the displacement of the point of the wheel initially in contact with the ground is [ CBSE-PMT 2002]
  • a)π
    ch-6_qn-27choice_img_no4.png
  • b)2 π
  • c)π √2
  • d)
Q.2
A thin circular ring of mass M and radius r is rotating about its axis with a constant angular velocity ω. Four objects each of mass m, are kept gently to the opposite ends of two perpendicular diameters of the ring. The angular velocity of the ring will be [2003]
  • a)
    ch-6_qn-28choice_img_no1.png
  • b)
    ch-6_qn-28choice_img_no2.png
  • c)
    ch-6_qn-28choice_img_no3.png
  • d)
    ch-6_qn-28choice_img_no4.png
Q.3
A small mass attached to a string rotates on frictionless table top as shown. If the tension in the string is increased by pulling the string causing the radius of the circular motion to decrease by a factor of 2, the kinetic energy of the mass will [ CBSE-PMT 2011]
ch-6_que_no-29_img_no1.png
  • a) remain constant
  • b) increase by a factor of 2
  • c) increase by a factor of 4
  • d) decrease by a factor of 2
Q.4
A gramophone record is revolving with an angular velocity ω. A coin is placed at a distance r from the centre of the record. The static coefficient of friction is µ The coin will revolve with the record if: [ CBSE-PMT 2010]
  • c) r ≤ µg / ω2
  • d) r ≥ µg / ω2
  • a) r = µgω 2
  • b) r < ω2 / µg
Q.5
A circular disk of moment of inertia It is rotating in a horizontal plane, its symmetry axis, with a constant angular speed ωi Another disk of moment of inertia Ib is dropped coaxially onto the rotating disk. Initially the second disk has zero angular speed. Eventually both the disks rotate with a constant angular speed ωf. The energy lost by the initially rotating disk to friction is: [ CBSE-PMT 2010]
  • a)
    ch-6_qn-31choice_img_no1.png
  • b)
    ch-6_qn-31choice_img_no2.png
  • c)
    ch-6_qn-31choice_img_no3.png
  • d)
    ch-6_qn-31choice_img_no4.png
Q.6
A solid sphere, disc and solid cylinder all of the same mass and made of the same material are allowed to roll down (from rest) on the inclined plane, then [1993]
  • a) solid sphere reaches the bottom first
  • b) solid sphere reaches the bottom last
  • c) disc will reach the bottom first
  • d) all reach the bottom at the same time
Q.7
The ratio of the radii of gyration of a circular disc about a tangential axis in the plane of the disc and of a circular ring of the same radius about a tangential axis in the plane of the ring is [2004]
  • a) 1 : √2
  • b) 1:3
  • c)2:1
  • d)√5: √6
Q.8
A boy suddenly comes and sits on a circular rotating table. What will remain conserved?[ CBSE-PMT 2002]
  • a) Angular velocity
  • b) Angular momentum
  • c)Linear momentum
  • d) Kinetic energy
Q.9
A solid cylinder of mass M and radius R rolls without slipping down an inclined plane of length L and height h. What is the speed of its centre of mass when the cylinder reaches its bottom ? [2003]
  • a)
    ch-6_qn-35choice_img_no1.png
  • b)
    ch-6_qn-35choice_img_no2.png
  • c)
    ch-6_qn-35choice_img_no3.png
  • d)
    ch-6_qn-35choice_img_no4.png
Q.10
Three particles, each of mass m gram, are situated at the vertices of an equilateral triangle ABC of side l cm (as shown in the figure). The moment of inertia of the system about a line AX perpendicular to A.B and in the plane of ABC, in gram-cm2 units will be [ CBSE-PMT 2004]
ch-6_que_no-36_img_no1.png
  • a)
    ch-6_qn-36choice_img_no1.png
  • b)
    ch-6_qn-36choice_img_no2.png
  • c)
    ch-6_qn-36choice_img_no3.png
  • d)
    ch-6_qn-36choice_img_no4.png
Q.11
A weightless ladder 20 ft long rests against a frictionless wall at an angle of 60° from the horizontal. A 150 pound man is 4 ft from the top of the ladder. A horizontal force is needed to keep it from slipping. Choose the correct magnitude of the force from the following [ CBSE-PMT 1998]
  • a)175lb
  • b) 100lb
  • c)120lb
  • d)69.21lb
Q.12
A constant torque of 1000 N-m turns a wheel of moment of inertia 200 kg-m2 about an axis through its centre. Its angular velocity after 3 seconds is [ CBSE-PMT 2001]
  • a) 1 rad/s
  • b) 5 rad/s
  • c) 10 rad/s
  • d) 15 rad/s
Q.13
A wheel having moment of inertia 2 kg-m2 about its vertical axis, rotates at the rate of 60 rpm about this axis. The torque which can stop the wheel's rotation in one minute would be [ CBSE-PMT 2004]
  • a) (π/18) N-m
  • b) (2π/15) N-m
  • c) (π/12) N-m
  • d) (π/15) N-m
Q.14
The moment of inertia of a uniform circular disc of radius R and mass M about an axis passing from the edge of the disc and normal to the disc is : [ CBSE-PMT 2005]
  • a) MR2
  • b) (1/2) MR2
  • c) (3/2)MR2
  • d) (7/2) MR2
Q.15
The moment of inertia of a thin uniform rod of mass M and length L about an axis passing through its midpoint and perpendicular to its length is IIts moment of inertia about an axis passing through one of its ends and perpendicular to its length is [ CBSE-PMT 2011]
  • a)I0 + ML2 /2
  • b) I0 + ML2 /4
  • c)I0 + 2ML2
  • d)I0 + ML2
Q.16
Two bodies of mass 1 kg and 3 kg have position vectors i + 2j + k and -3i - 2j + k respectively. The center of mass of this system has a position vector: [ CBSE-PMT 2009]
  • a) -2i - j + k
  • b) 2i - j - 2k
  • c)-j + j + k
  • d)-2i + 2k
Q.17
The instantaneous angular position of a point on a rotating wheel is given by the equation a(t)=2t3 - 6tThe torque on the wheel becomes zero at [ CBSE-PMT 2011]
  • a)t=1s
  • b) t=0.5s
  • c)t=0.25s
  • d)t=2s
Q.18
A thin rod of length L and mass M is bent at its midpoint into two halves so that the angle between them is 90째. The moment of inertia of the bent rod about an axis passing through the bending point and perpendicular to the plane defined by the two halves of the rod is:[2008]
  • a) ML2/24
    ch-6_qn-44choice_img_no4.png
  • b) ML2/12
  • c) ML2/6
  • d)
Q.19
A particle of mass m moves in XY plane with a velocity 'v' along the straight line AB. If the angular momentum of the particle with respect to origin O is LA when it is at A and LB when it is at B then .. [ CBSE -PME 2007]
ch-6_que_no-45_img_no1.png
  • a)LA=LB
  • b) The relationship between LA and LB depends upon the slope of the line
  • c)LA < LB
  • d)LA > LB
Q.20
The moment of inertia of a body about a given axis is 1.2 kg mInitially, the body is at rest. In order to produce a rotational kinetic energy of 1500 joule, an angular acceleration of 25 radian/sec2 must be applied about that axis for a duration of [ CBSE- PMT 1990]
  • a) 4 seconds
  • b) 2 seconds
  • c)8 seconds
  • d)10 seconds
Q.21
rectangle ABCD (BC=2 AB). The moment of inertia is minimum along axis through [ CBSE-PMT 1993]
ch-6_que_no-47_img_no1.png
  • a) BC
  • b) BD
  • c)HF
  • d)EG
Q.22
The centre of mass of a system of particles does not depend upon [ CBSE-PMT 1997]
  • a) masses of the particles
  • b) forces acting on the particles
  • c) position of the particles
  • d) relative distances between the particles
Q.23
If the linear density (mass per unit length) of a rod of length 3m is proportional to x, where x is the distance from one end of the rod, the distance of the centre of gravity of the rod from this end is [ CBSE-PMT 2002]
  • a) 2.5m
  • b) 1m
  • c)1.5m
  • d)2m
Q.24
Consider a system of two particles having masses m1 and mIf the particle of mass m1 is pushed towards the centre of mass of particles through a distance d, by what distance would the particle of mass m2 move so as to keep the centre of mass of particles at the original position? [ CBSE-PMT 2004]
  • a)
    ch-6_qn-51choice_img_no1.png
  • b)
    ch-6_qn-51choice_img_no2.png
  • c)
    ch-6_qn-51choice_img_no3.png
  • d)d
Q.25
A drum of radius R and mass M, rolls down without slipping along an inclined plane of angle θ. The fractional force [ CBSE-PMT 2005]
  • a) dissipates energy as heat
  • b) decreases the rotational motion
  • c) decreases the rotational and transnational motion
  • d) converts transnational energy to rotational energy
Q.26
A thin circular ring of mass M and radius r is rotating about its axis with a constant angular velocity ω, two objects, each of mass m, are attached gently to the opposite ends of a diameter of the ring. The wheel now rotates with an angular velocity [ IIT 1983]
  • a)ωM / ( M + m)
  • b) ω(M - 2m) / ( M + 2m)
  • c)ωM / ( M + 2m)
  • d)ω(M + 2m) / M
Q.27
Two point masses of 0.3kg and 0.7kg are fixed at the ends of a rod of length 1.4m and of negligible mass. The rod is set to rotate about an axis perpendicular to its length with a uniform angular speed. The point on the rod through which the axis should pass in order that the work required for rotation of the rod is minimum, is located at a distance of .. [ AIEEE 1995]
  • a) 0.42m from mass of 0.3kg
  • b) 0.70 m from mass of 0.7kg
  • c)0.98 m from mass of 0.3kg
  • d)0.98 m from mass of 0.7kg
Q.28
A mass 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 [ IIT 1997]
  • a) is zero
  • b) remains constant
  • c)goes on increasing
  • d)goes on decreasing
Q.29
A cubical block of side a is moving with velocity V on a horizontal smooth plane as shown in figure. It hits a ridge at point O. The angular speed of the block after it hits O is [ IIT 1999]
ch-6_que_no-56_img_no1.png
  • a) 3V / (4a)
  • b) 3V/(2a)
  • c) (3V/2a) 1/2
  • d) zero
Q.30
A cyclist turns around a curve at 15 miles per hour. If turns at double the speed, the tendency to overturn is
  • a)doubled
  • b) quadrupled
  • c)halved
  • d)unchanged
0 h : 0 m : 1 s