Q.1
A body is revolving with a constant speed along a circular path. If the direction of velocity is reversed, keeping speed unchanged, then
  • a) Centripetal force suffer change in magnitude but not direction
  • b) The centripetal force does not suffer any change in direction and magnitude
  • c)centripetal force reverses in direction
  • d)centripetal force is doubled
Q.2
An earth satellite is moving around the earth in a circular orbit. In such a case, what is conserved? [ DEC 2001]
  • a) velocity
  • b) linear momentum
  • c)angular momentum
  • d)none of the above
Q.3
The acceleration of solid cylinder rolling down an inclined plane of inclination 30° is [ DPMT 2002]
  • a) g/3
  • b) g/2
  • c)g
  • d)g/4
Q.4
A particle is projected with 200 m/s at an angle 60°. At the highest point, it explodes into three parts of equal masses. One goes vertically upwards with velocity 100 m/s, second particle goes vertically downwards. Then the velocity of the third particle will be..[ AFMC 1997]
  • a)200 m/s
  • b) 300 m/s
  • c)120 m/s with 60° angle
  • d)200 m/s with 30°angle
Q.5
A bird weight 2 kg and is inside a cage of 1kg. If it starts flying then the weight of the bird and cage assembly is [ AFMC 1997]
  • a) 4 kg
  • b) 3 kg
  • c)2.5 kg
  • d)1.5 kg
Q.6
A solid cylinder of 500g and radius 10cm has moment of inertia about its natural axis ...[ AFMC 1997]
  • a) 3.5 kg m2
  • b) 5 × 10-3 kg m2
  • c)2 × 10-3 kg m2
  • d)2.5 × 10-3 kg m2
Q.7
A particle performs uniform circular motion with an angular momentum L. If the frequency of the particle motion is doubled and its kinetic energy is halved, the angular momentum becomes..[ AFMC 1998]
  • a) L/4
  • b) L/2
  • c) 2 L
  • d) 4L
Q.8
A bob of mass 10kg is attached to a wire 0.3m long. Its breaking stress is 4.8×107 NmThe area of cross-section of the wire is 10-6 mWhat is the maximum angular velocity with which it can be rotated in a horizontal circle..[AFMC 1998]
  • a)8 rad/s
  • b) 4 rad/s
  • c)2 rad/s
  • d)1 rad/s
Q.9
A cord is wound round the circumference of the wheel of radius r. The axis of the wheel is horizontal and the moment of inertia about the centre is I. A weight mg is attached to the cord at the end. The weight falls from rest. After falling through distance h, angular velocity of the wheel is [ AFMC 1998]
  • a)
    ch-6_qn-6choice_img_no1.png
  • b)
    ch-6_qn-6choice_img_no2.png
  • c)
    ch-6_qn-6choice_img_no3.png
  • d)
    ch-6_qn-6choice_img_no4.png
Q.10
A body of 2kg mass is rotating on a circular path of radius 0.8m with an angular velocity 44 rad/sec. If radius of the path becomes 1 m then value of angular velocity will be...[ AFMC 1998]
  • a) 35.28 rad/sec
  • b)14.08 rad/sec
  • c)28.16 rad/sec
  • d)24.08 rad/sec
Q.11
A stone tied to one end of string of 1m long is whirled in a horizontal circle with a constant speed. if the stone makes 10 revolutions in 20 sec, the magnitude of the acceleration of the stone is ...[ AFMC 1998]
  • a) 988 cm/s2
  • b) 490 cm/s2
  • c) 986 cm/s2
  • d) 996 cm/s2
Q.12
The moment of inertia of a regular circular disc of mass 0.4 kg and radius 100cm about the axis perpendicular to the plane of the disc and passing through its centre is [ AFMC 2000]
  • a)0.002 kg m2
  • b) 0.02kg m2
  • c)2kg m2
  • d)0.2 kg m2
Q.13
The angular velocity of second's hand in a watch is ..[AFMC 2000]
  • a) 0.82 rad/sec
  • b) 0.105 rad/sec
  • c)0.21 rad/sec
  • d)0.052 rad/sec
Q.14
Two particles of equal mass revolving in circular paths of radii r1 and r2 respectively with the same angular velocity. The ratio of their centripetal force will be ....[ AFMC 2011]
  • a) r1 /r2
  • b) r2 / r1
  • c)(r2 / r1) 1/2
  • d)(r2 / r1) 2
Q.15
A body of mass 5 kg is moving in a circle of radius 1m with an angular velocity of 2 rad/sec. The centripetal force acting on the body is ...[ AFMC 2002]
  • a) 20 N
  • b) 10 N
  • c) 5N
  • d) 15 N
Q.16
Moment of inertia of a 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 [ CBSE-PMT 1990]
  • a)5I
  • b) 3I
  • c)6I
  • d)4I
Q.17
A particle of mass m=5 is moving with a uniform speed v=3√2 in XOY plane along the line y=x +The magnitude of the angular momentum of the particle about the origin is [ CBSE-PMT 1991]
  • a) 60 units
  • b) 40√2 units
  • c) zero
  • d)7.5 units
Q.18
particle of mass m is moving in a horizontal circle of radius R with uniform speed v. When it moves from one point to a diametrically opposite point, its [1989]
  • a) kinetic energy changes by mv2/4
  • b) momentum does not change
  • c) momentum changes by 2 mv
  • d)kinetic energy changes by mv2
Q.19
The speed of a homogenous solid sphere after rolling down an inclined plane of vertical height h from rest without sliding is [ CBSE-PMT 1992]
  • a)
    ch-6_qn-16choice_img_no1.png
  • b)
    ch-6_qn-16choice_img_no2.png
  • c)
    ch-6_qn-16choice_img_no3.png
  • d)
    ch-6_qn-16choice_img_no4.png
Q.20
The angular speed of an engine wheel making 90 revolutions per minute is [ CBSE-PMT 1995]
  • a)1.5 π rad/s
  • b) 3 π rad/s
  • c)4.5 π rad/s
  • d)6 π rad/s
Q.21
Two racing cars of masses 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 time t. The ratio of the angular speeds of the first to the second car is [ CBSE - PMT 1999]
  • a) 1 : 1
  • b) m1 : m2
  • c)r1 ,r2
  • d) m1, m2 : r1r2
Q.22
O is the centre of an equilateral triangle ABC. F1, F2 and F3 are three forces acting along the sides AB, BC and AC as shown here. What should be the magnitude of F3, so that the total torque about O is zero? [ CBSE - PMT 1998]
ch-6_que_no-19_img_no1.png
  • a)(F1 + F2) /2
  • b) 2(F1 + F2)
  • c)(F1 + F2)
  • d)(F1 - F2)
Q.23
A disc is rotating with angular velocity ω. If a child sits on it, what is conserved ? [ CBSE-PMT 2002]
  • a) Linear momentum
  • b) Angular momentum
  • c) Kinetic energy
  • d) Moment of inertia
Q.24
A fly wheel rotating about a fixed axis has a kinetic energy of 360 joule when its angular speed is 30 radian/sec. The moment of inertia of the wheel about the axis of rotation is [ CBSE-PMT 1990]
  • a)0.6kg/m2
  • b) 0.15kgm2
  • c)0.8 kg m2
  • d)0.75 kg m2
Q.25
A solid cylinder and a hollow cylinder both of the same mass and same external diameter, are released from the same height at the same time on an inclined plane. Both roll down without slipping. Which one will reach the bottom first?[ CBSE-PMT 2000]
  • a) Both together
  • b) Solid cylinder
  • c) One with higher density
  • d)Hollow cylinder
Q.26
A composite disc is to be made using equal masses of aluminum and iron so that it has as high a moment of inertia as possible. This is possible when [ CBSE-PMT 2002]
  • a)the surfaces of the discs are made of iron with aluminum inside
  • b) the whole of aluminum is kept in the core and the iron at the outer rim of the disc
  • c) the whole of the iron is kept in the core and the aluminum at the outer rim of the disc
  • d)the whole disc is made with thin alternate sheets of iron and aluminum
Q.27
When a torque acting upon a system is zero, which of the following will be constant? [ J and K CET 2002]
  • a) force
  • b) linear momentum
  • c) linear impulse
  • d) none of these
Q.28
A spherical ball rolls on a table without slipping. Then the fraction of its total energy associated with rotation is [ CBSE-PMT 1994]
  • a) 2/5
  • b) 2/7
  • c) 3/5
  • d) 3/7
Q.29
ABC is a triangular plate of uniform thickness. The sides are in the ratio shown in the figure. IAB, IBC. and ICA are the moments of inertia of the plate about AB, BC and CA as axes respectively. Which one of the following relations is correct?[ CBSE- PMT 1995]
ch-6_que_no-25_img_no1.png
  • a)IAB > IBC
  • b) IBC > IAB
  • c)IAB + IBC=ICA
  • d)ICA is maximum
Q.30
A couple produces [ CBSE-PMT 1997]
  • a) no motion
  • b) purely linear motion
  • c)purely rotational motion
  • d)linear and rotational
0 h : 0 m : 1 s