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
-
50%
a) lighter piece
-
12%
b) heavier piece
-
25%
c)depends on the vertical velocity at the time of breaking
-
12%
d)does 't shift horizontally
Q.2.
A sphere can not roll on
-
50%
a) a smooth inclined surface
-
0%
b) a smooth horizontal surface
-
33%
c) a rough inclined surface
-
17%
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]
-
20%
a)m1 : m2
-
20%
b) r1 : r2
-
60%
c)1:1
-
0%
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]
-
20%
a) 1:1
-
40%
b) 2:1
-
40%
c)4:1
-
0%
d)1:2
Explanation
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]
-
40%
a) increase
-
40%
b) decrease
-
20%
c)remain the same
-
0%
d)nothing can be said
Q.6.
When a body rolls down an inclined plane, its potential energy is converted into [ CBSE 1996]
-
0%
a) translational K.E only
-
0%
b) rotational K.E only
-
100%
c) translational and rotational K.E
-
0%
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]
-
0%
a) =1
-
60%
b) < 1
-
20%
c) > 1
-
20%
d) none of the above
Q.8.
A couple produces a ... [ pre-medical dental, 1997]
-
20%
a) pure linear motion
-
60%
b) pure rotational motion
-
20%
c) both linear and rotational motion
-
0%
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]
-
0%
a) 7:10
-
20%
b) 2:5
-
40%
c) 10:7
-
40%
d) 2:7
Explanation
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]
-
0%
a) 5:3
-
25%
b) 3:5
-
75%
c) √5 : √3
-
0%
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
-
25%
a)ring
-
0%
b) cylinder
-
0%
c)spherical shell
-
75%
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]
-
0%
a) 2/3( tan α)
-
25%
b) 2/7 (tan α)
-
25%
c)1/3 (tanα)
-
50%
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]
-
0%
a) zero
-
75%
b) constant
-
0%
c)goes on decreasing
-
25%
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]
-
0%
a) horizontal surface
-
0%
b) centre of one of the balls
-
0%
c) line joining centre of any two balls
-
100%
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]
-
0%
a)(3/2) MR2
-
25%
b) (2/5) MR2
-
50%
c)(5/4) MR2
-
25%
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]
-
50%
a) L/ √12
-
0%
b) L2 / 12
-
50%
c)L/√3
-
0%
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]
-
50%
a) π/2
-
25%
b) π/4
-
0%
c)π/6
-
25%
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)
-
25%
a) 4 m/s
-
0%
b) 2 m/s
-
25%
c) 10 m/s
-
50%
d) 8 m/s
Explanation
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]
-
33%
a)
-
0%
b)
-
33%
c)½ MR2
-
33%
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]
-
50%
a)45
-
25%
b) 182
-
25%
c)187
-
0%
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]
-
50%
a) (PQ + PR + QR) / 3
-
50%
b) (PQ + PR) / 3
-
0%
c)(PQ + QR) / 3
-
0%
d)(PQ + QR + PR) / 3
Explanation
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]
-
0%
a)0.8
-
50%
b) 0.4
-
25%
c)0.2
-
25%
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]
-
100%
a) water levels in both section A and B goes up
-
0%
b) water level in section A goes up and then in section B comes down
-
0%
c) Water level in section A comes down and then in B goes up
-
0%
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]
-
75%
a)(3/4)A0
-
0%
b) A0
-
0%
c)4A0
-
25%
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]
-
0%
a) g/3
-
75%
b) 2g/3
-
0%
c)5g/7
-
25%
d)5g/14
Explanation
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]
-
0%
a) 40 gm cm2
-
25%
b) 300 gm cm2
-
25%
c)200 gm cm2
-
50%
d)100 gm cm2
Q.27.
Moment of momentum is called
-
25%
a) torque
-
0%
b) weight
-
0%
ac) moment of inertia
-
75%
d) angular momentum
Q.28.
A dancer on ice spins faster when she folds her hand. This is due to [ CPMT 1986]
-
0%
a)increase in energy and increase in angular momentum
-
0%
b) decrease in friction at the skates
-
50%
c)constant angular momentum and increase in kinetic energy
-
50%
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]
-
0%
a) EI
-
50%
b) 2 √(EI)
-
25%
c) √(2EI)
-
25%
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]
-
0%
a) 1.2 kg m/s
-
25%
b) 1.0 kg m/s
-
0%
c)0.6 kg m/s
-
75%
d)none of the above