CBSE Questions for Class 11 Engineering Physics Systems Of Particles And Rotational Motion Quiz 4 - MCQExams.com

A stone is dropped from a height $$h$$. It hits the ground with a certain momentum $$P$$. If the same stone is dropped from a height $$100$$% more than the previous height, the momentum when it hits the ground will change by (approximately) :
  • $$41$$%
  • $$53$$%
  • $$60$$%
  • $$68$$%
The passengers in a boat are not allowed to stand because: 
  • This will raise the centre of gravity and the boat will be rocked
  • This will lower centre of gravity and the boat will rocked
  • The effective weight of system increases
  • Of surface tension effects
Two particles of mass 1 kg and 0.5 kg are moving in the same direction with speed of 2 m/s and 6 m/s respectively on a smooth horizontal surface. The speed of centre of mass of the system is
  • $$\displaystyle\frac{10}{3}$$ m/s
  • $$\displaystyle\frac{10}{7}$$ m/s
  • $$\displaystyle\frac{11}{2}$$ m/s
  • $$\displaystyle\frac{12}{3}$$ m/s
A uniform disc of mass M and radius R is mounted on an axle supported in friction less bearings. A light cord is wrapped around the rim of the disc and a steady downward pull T is exerted on the cord. The angular acceleration of the disc is:
  • $$\displaystyle \frac{MR}{2 T}$$
  • $$\displaystyle \frac{2T}{MR}$$
  • $$\displaystyle \frac{T}{MR}$$
  • $$\displaystyle \frac{MR}{T}$$
A spinning top exhibits rectilinear motion. True or false.
  • True
  • False
The momentum of a body of mass $$0.5$$ kg dropped from a certain height (h), when reaches the ground is $$10$$ N s. The value h is ___ m. ( g$$\displaystyle {= 10\ ms }^{ -2 }$$)
  • $$20$$
  • $$40$$
  • $$10$$
  • $$80$$
A body of mass 100 g is moving with a velocity of 15 m/s. The momentum associated with the ball will be :
  • 0.5 kg m/s
  • 1.5 kg m/s
  • 2.5 kg m/s
  • 3.2 Ns
A solid cylinder of radius r rolls down on an inclined plane without slipping. The speed of the centre of mass when it reaches the bottom, is:
  • $$\sqrt{2 gh}$$
  • $$\sqrt{4 g}$$
  • $$\sqrt{3 gh/4}$$
  • $$\sqrt{4gh/3}$$
If a body of mass M collides against a wall with velocity V and rebounds with the same speed, then its change of momentum will be 
  • Zero
  • MV
  • 2MV
  • -2MV
Moment of inertia of thin uniform rod of length $$\displaystyle l$$ is equal to: 
  • $$\displaystyle \frac { { ml }^{ 2 } }{ 6 } $$
  • $$\displaystyle \frac { { ml }^{ 2 } }{ 12 } $$
  • $$\displaystyle \frac { { ml }^{ 2 } }{ 4 } $$
  • $$\displaystyle \frac { { ml }^{ 2 } }{ 24 } $$
A lead ball and rubber ball having same mass, strike normally on a smooth vertical wall with the same velocity. The lead ball falls down after striking but the rubber ball bounces back. Then
  • momentum oflead ball is greater than that of rubber ball
  • momentum of rubber ball is greater than that of lead ball
  • the rubber ball suffers a greater change in momentum as compared to lead ball
  • both the balls suffer an equal change in momentum
A body of mass 5 kg undergoes a change in speed from 30 to 40 m/s. Its momentum would increase by :
  • 50 kg m/s
  • 75 kg m/s
  • 150 kg m/s
  • 350 kg m/s
A body of mass $${ m }_{ 1 }=4 \ kg$$ moves at $$5i \ m/s$$ and another body of mass $${ m }_{ 2 }=2 \ kg$$ moves at $$10 i\ m/ s$$. The kinetic energy of centre of mass is
  • $$\dfrac{200 }{ 3} J$$
  • $$\dfrac{500 }{ 3} J$$
  • $$\dfrac{400 }{ 3} J$$
  • $$\dfrac{800 }{ 3} J$$
The radius of gyration of a body about an axis at a distance 6 cm from its centre of mass is 10 cm. Then, its radius of gyration about a parallel axis through its centre of mass will be :
  • 80 cm
  • 8 cm
  • 0.8 cm
  • 80 m
The moment of inertia of a solid sphere about an axis passing through centre of gravity is $$\dfrac {2}{5}MR^{2}$$, then its radius of gyration about a parallel axis at a distance $$2R$$ from first axis is
  • $$5 R$$
  • $$225\sqrt {R}$$
  • $$\dfrac {5}{2}R$$
  • $$\sqrt {\dfrac {12}{5}}R$$
The ratio of angular speeds of minute hand and hour hand of a watch is.
  • $$1:12$$
  • $$6:1$$
  • $$12:1$$
  • $$1:6$$
The angular speed of a body changes from $$\omega_{1}$$ to $$\omega_{2}$$ without applying a torque but due to changes in moment of inertia. The ratio of radii of gyration in two cases is
  • $$\sqrt {\omega_{2}} : \sqrt {\omega_{1}}$$
  • 1
  • $$\sqrt {\omega_{2}^{2}} : \sqrt {\omega_{1}^{2}}$$
  • $$\sqrt {\omega_{2}^{3}} : \sqrt {\omega_{1}^{3}}$$
The moment of inertia of a thin uniform rod rotating about the perpendicular axis passing through one end is $$I$$. The same rod is bent into a ring and its moment of inertia about the diameter is $${I}_{1}$$. The ratio $$\dfrac{I}{{I}_{1}}$$ is
  • $$\dfrac{4\pi}{3}$$
  • $$\dfrac{8{\pi}^{2}}{3}$$
  • $$\dfrac{5\pi}{3}$$
  • $$\dfrac{8{\pi}^{2}}{5}$$
What torque will increase angular velocity of a solid disc of mass $$16kg$$ and diameter $$1m$$ from zero to $$2$$rpm in $$8s$$?
  • $$\cfrac { \pi }{ 4 } N-m$$
  • $$\cfrac { \pi }{ 2 } N-m$$
  • $$\cfrac { \pi }{ 3 } N-m$$
  • $$\pi N-m$$
A couple produces :
  • no motion
  • linear and rotational motion
  • purely rotational motion
  • purely linear motion
A particle is projected at an angle of $${30}^{0}$$ with the horizontal with a momentum $$P$$. At the highest point its momentum is
  • $$\dfrac { \sqrt { 3 } }{ 2} P$$
  • $$\dfrac { 2 }{ \sqrt { 3 } } P$$
  • $$P$$
  • $$\dfrac { 1 }{ 2 } P$$
Which one of the following is a scalar quantity?
  • Displacement
  • Velocity
  • Acceleration
  • Linear momentum
  • Kinetic energy
A body of mass $$1\ kg$$ is thrown with a velocity of $$\displaystyle 10{ ms }^{ -1 }$$ at an angle of $$\displaystyle { 60 }^{ \circ  }$$ with the horizontal. Its momentum at the highest point is:
  • $$\displaystyle 2\ kg\ { ms }^{ -1 }$$
  • $$\displaystyle 3\ kg\ { ms }^{- 1 }$$
  • $$\displaystyle 4\ kg\ { ms }^{ -1 }$$
  • $$\displaystyle 5\ kg\ { ms }^{ -1 }$$
A $$2.5 kg$$ ball is dropped onto a concrete floor. It strikes the floor with a momentum of $$20 kgm/s$$ and bounces away from the floor with a momentum of $$16 kgm/s$$.What is the magnitude of change of momentum of the ball?
  • $$4 kg.m/s$$
  • $$8 kgm/s$$
  • $$32 kgm/s$$
  • $$36 kgm/s$$
  • $$40 kgm/s$$
A student performed an experiment and records the mass and speed of an object traveling at the constant velocity on a frictionless track. Find out which of above trial had the greatest momentum and  the trial in which it had the greatest kinetic energy.

Greatest Momentum      Greatest Kinetic Energy

479885.jpg
  • Trial 1 Trial 3
  • Trial 2 Trial 2
  • Trial 3 Trial 2
  • Trial 3 Trial 3
  • Trial 4 Trial 4
An object is moving with velocity V. The velocity of a moving object is gets doubled. Identify which of the following statements about the moving object is correct?
  • The kinetic energy of the object increases by four
  • The displacement of the object increases by four
  • The momentum of the object increases by four
  • The frictional force increases by four
  • None of these quantities increase by four
Two point objects of masses 1.5 g and 2.5 g respectively are at a distance of 16 cm apart, the centre of gravity is at a distance x from the object of mass 1.5 g where x is:
  • 10 cm
  • 6 cm
  • 13 cm
  • 3 cm
Find out the magnitude of the change in momentum of the object between $$t=0$$ and $$t=0.4$$ sec from the given graph between Total force acting on an object vs Time ?
479868.jpg
  • $$2 kg-{m}/{sec}$$
  • $$5 kg-{m}/{sec}$$
  • $$10 kg-{m}/{sec}$$
  • $$12 kg-{m}/{sec}$$
  • $$15 kg-{m}/{sec}$$
The velocity vs Time graph of an object travelling in a straight line is given. 
Select the correct option for the momentum vs time graph of the particle.
479789.jpg
The point through which the total weight of an object appears to act for any orientation of the object is ______.
  • Centre of buoyancy
  • Centre of gravity
  • Centre of curvature
  • Median of a triangle
A force acts on a mass and its variation with time is shown in the above graph. 
Find out the change in momentum of the mass between 2s and 5s ?

486989.png
  • 9 kg.m/s.
  • 18 kg.m/s.
  • 21 kg.m/s.
  • 30 kg.m/s.
  • 42 kg.m/s.
How should the mass of a rotating body of radius r be distributed so as to maximize its angular velocity?
  • The mass should be concentrated at the outer edge of the body
  • The mass should be evenly distributed throughout the body
  • The mass should be concentrated at the axis of rotation
  • The mass should be concentrated at a point midway between the axis of rotation and the outer edge of the body
  • Mass distribution has no impact on angular velocity
Two bodies of unequal masses possess the same momentum. Which of the following can be concluded?
  • Heavier mass possesses lesser K.E
  • The masses of the two bodies are in the direct ratio of their velocities
  • Lighter mass possesses less K.E,
  • Both (A) and (B)
In above shown figure, a ball of mass 4 kg slides over frictionless surface and strikes the post with velocity of 1 m/s and rebounds toward the north at the same speed. The change in the magnitude of the eastward component of the momentum of the disk is:
484594.png
  • -4kg.m/s
  • -1kg.m/s
  • 0kg.m/s
  • 1kg.m/s
  • 4kg.m/s
Refer to two 1 kg masses moving toward each other, one mass with velocity $$v_1$$= 10 m/s, the other with velocity $$v_2$$= 20 m/s. What is the velocity of the center of mass?
491206_13037a5b9633415094a5577c1cf0d9c0.png
  • 0 m/s
  • 5 m/s to the left
  • 10 m/s to the left
  • 15 m/s to the left
  • 20 m/s to the left
A large, massive man and a small boy of small mass are held far apart on an icy surface where friction is negligible. The man and the boy hold opposite ends of a bungee cord that is stretched.
When the boy and the man are released, they are each pulled by the bungee cord so that they approach one another.
When they get close to each other, how will their momenta, velocity, and kinetic energies compare?
  • Magnitude of Momenta - man's greater then boy's, Magnitude of Velocity - boy's greater than man's, Kinetic Energy - man's greater than boy's
  • Magnitude of Momenta - same for both, Magnitude of Velocity - boy's greater than man's, Kinetic Energy - same for both
  • Magnitude of Momenta - same for both, Magnitude of Velocity - same for both, Kinetic Energy - same for both
  • Magnitude of Momenta - boy's greater then man's, Magnitude of Velocity - boy's greater than man's, Kinetic Energy - same for both
  • Magnitude of Momenta - same for both, Magnitude of Velocity - boy's greater than man's, Kinetic Energy - boy's greater than man's
A filled shopping cart (30.0kg) is being pushed rapidly toward the back of a store so that its velocity is 2.0 m/s. What is the momentum of the cart. and what is the kinetic energy of the cart?
  • $$90 kg m/s $$ and $$60 J$$
  • $$60 kg m/s $$ and $$90 J$$
  • $$60 kg m/s $$ and $$60 J$$
  • $$90 kg m/s $$ and $$90 J$$
Find out the velocity of the centre of mass of two $$1 kg$$ masses moving toward each other, one mass with velocity $${v}_{1} = 10 {m}/{s}$$, the other with velocity $${v}_{2} = 20 {m}/{s}$$.


482847.jpg
  • $$0 {m}/{s}$$
  • $$5 {m}/{s}$$ to the left
  • $$10 {m}/{s}$$ to the left
  • $$15 {m}/{s}$$ to the left
  • $$20 {m}/{s}$$ to the left
Rank the order of the magnitude of the momenta of the four objects pictured above, greatest first. Masses are shown inside the boundaries of the objects. Velocities are shown with the red arrows ant the corresponding values.
492663.jpg
  • blue and yellow tie, green and purple and orange tie
  • purple and orange tie, blue, yellow, green
  • blue, purple and orange tie, green yellow
  • green and purple tie, or orange, blue and yellow tie
  • green and purple and orange tie, blue and yellow tie
Which of the following quantities is zero, when a uniform object is being supported at its centre of gravity?
  • Mass
  • Weight
  • Force
  • Moment
State whether true or false.
A couple can never be replaced by a single force.
  • True
  • False
The kinetic energy of a body of mass $$4\ kg$$ and momentum $$6\ Ns$$ will be
  • $$2.5\ J$$
  • $$3.5\ J$$
  • $$4.5\ J$$
  • $$5.5\ J$$
A bucket is being lowered down into a wall through a rope passing over a fixed pulley f radius 10 cm. Assume that the rope does  not slip on the pulley. Find the angular acceleration of the pulley at an instant when the bucket is going down at a speed of 20 cm/s and has a acceleration of $$4 ms^{-2}$$. 
  • $$10 \ rad \ s^{-2}$$
  • $$20 \ rad \ s^{-2}$$
  • $$30 \ rad \ s^{-2}$$
  • $$40 \ rad \ s^{-2}$$
State whether true or false.
A couple tends to produce motion in a straight line.
  • True
  • False
The total angular momentum of a rigid body can be written as 
  • $$ I \times \omega $$ ; where I: moment of inertia of body, : angular velocity
  • $$I^2 \times \omega $$; where I: moment of inertia of body, : angular velocity
  • $$ I^2 \times {\omega}^2$$; where I: moment of inertia of body, : angular velocity
  • $$I \times {\omega}^2$$ ; where I: moment of inertia of body, : angular velocity
State whether true or false.
Only a couple can produce pure rotation in a body.
  • True
  • False
State whether true or false.
The centre of gravity of regular shaped objects is at their geometric centre.
  • True
  • False
What is the momentum of a $$6.0 kg$$ bowling ball with a velocity of $$2.2 {m}/{s}$$?
  • 11.2
  • 17.2
  • 15.2
  • 13.2
An object will not undergo rotational motion when:
  • the forces are acting on it at different positions
  • every forces is creating different turning effects
  • every moment has the same amplitude
  • all the forces are acting at its centre of gravity
If v, P and E denote the velocity, momentum and kinetic energy of the particle, then:
  • P = dE/dv
  • P = dE/dt
  • P = dv/dt
  • none of these.
0:0:1


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