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CBSE Questions for Class 11 Engineering Physics Work,Energy And Power Quiz 4 - MCQExams.com

State whether the given statement is True or False :
The energy of an object that is due to the object's motion is called kinetic energy.
  • True
  • False
A boy is whirling a stone tied at one end such that the stone is in uniform circular motion.Which of the following statement is correct?
245814_7d3f89bb93574ce29b4797732a70bd81.png
  • The velocity of stone at A is equal to the velocity of stone B
  • The speed of stone at A is equal to the speed of stone at B.
  • The centripetal force is radially outward in the string.
  • All of the above statements are correct.
A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process, the potential energy of the car
  • does not change
  • becomes twice of initial
  • becomes 4 times of initial
  • becomes 16 times of initial
A mass is performing vertical circular motion (see figure). If the average velocity of the particle is increased, then at which point is the maximum breaking possibility of the string:
280422.bmp
  • A
  • B
  • C
  • D
A stone of mass 1kg is tied to the end of a string of 1m long. It is whirled in a vertical circle. If the velocity of the stone at the top be 4m/s. What is the tension in the string?
  • 6N
  • 16N
  • 5N
  • 10N
Two weights of 5 kg and 10 kg are placed on a horizontal table of height 1.5 m. Which will have more potential energy?
  • 5 kg
  • 10 kg
  • Both will have equal energy
  • None of the above
Which one of the following possesses potential energy?
  • Moving vehicle on the road
  • A running athlete
  • Stone on the road
  • A stretched rubber band
An overhead tank having some water possesses .......... energy.
  • Kinetic
  • Potential
  • Thermal
  • Electrical
When an arrow is released from a bow, potential energy changes into kinetic energy.
  • True
  • False
  • Ambiguous
  • Data insufficient
Energy possessed by a body by virtue of its motion is :
  • Potential energy
  • Kinetic energy
  • Chemical energy
  • Electrical energy
A student sitting at the top of a tree has ............ than the student who is sitting on the ground.
  • less potential energy
  • more potential energy
  • more kinetic energy
  • more gravitational energy
The form of energy present in a wound spring is:
  • chemical
  • heat energy
  • magnetic
  • mechanical
The energy directly related to the speed of a moving body and its mass is:
  • Kinetic
  • Potential
  • Solar
  • Electric
A boy holds a pendulum in his hand while standing at the edge of a circular platform of radius r rotating at an angular speed ω. The pendulum will hang at an angle θ with the verticle such that
  • tanθ=0
  • tanθ=ω2r2g
  • tanθ=rω2g
  • tanθ=gω2r
A mass tied to a string moves in a vertical circle with a uniform speed of 5m/s as shown. At the point P the string breaks. The mass will reach a height above P of nearly: (g=10 m/s2)
281289_9e5aee9304574026bff2f5a8515de9e6.png
  • 1m
  • 0.5m
  • 1.75m
  • 1.25m
A particle of mass m describes a circle of radius (r). The centripetal acceleration of the particle is 4r2. The momentum of the particle:
  • 2mr
  • 2mr
  • 4mr
  • 4mr
In a vertical circle of radius (r), at what point in its path a particle may have tension equal to zero:
  • highest point
  • lowest point
  • at any point
  • at a point horizontal from the centre of radius
A stone attached to one end of a string is whirled in a vertical circle. The tension in the string is maximum when
  • the string is horizontal
  • the string is vertical with the stone at highest position
  • the string is vertical with the stone at the lowest position
  • the string makes an angle of 45 with the vertical
A position dependent force F=72x+3x2N acts on a small object of mass 2kg to displace it from x=0 to x=5m. The work done in joules is-
  • 70
  • 270
  • 35
  • 135
A particle is moving in a vertical circle, the tension in the string when passing through two position at angle 30 and 60 from vertical from lowest position are T1 and T2 respectively, then 
  • T1=T2
  • T1>T2
  • T1<T2
  • T1T2
A pendulum bob has a speed 3m/s while passing through its lowest position, length of the pendulum is 0.5m then its speed when it makes an angle of 60 with the vertical is
  • 2m/s
  • 1m/s
  • 4m/s
  • 3m/s
A particle slides from rest from the topmost point of a vertical circle of radius (r) along a smooth chord making an angle (θ) with the vertical the time of decent is 
  • Least for θ=0
  • Maximum for θ=0
  • Least for θ=45
  • Independent of θ
A particle of mass m1 moving with a velocity of 5m/s collides head on with a stationary particle of mass m2. After collision both the particle move with a common velocity of 4m/s, then the value m1/m2 is:
  • 4:1
  • 2:1
  • 1:8
  • 1:2
A time dependent force F = 10 t is applied on 10 kg block. Find out the work done by F in 2 seconds.
  • 40 J
  • 20 J
  • 120 J
  • 60 J
Force shown acts for 2 seconds. Find out work done by force F on 10 kg in 3 seconds.
301887_761b4a987fc1439fa0f106fe720cb995.png
  • 30 J
  • 20 J
  • 50 J
  • 60 J
A force acts on a 3 gm particle in such a way that the position of the particle as a function of time is given by x=3t4t2+t3, where x is in meters and t is in seconds. The work done during the first 4 second is:
  • 384mJ
  • 168mJ
  • 528mJ
  • 541mJ
Under the action of a force, a 2kg mass moves such that its position x as a function of time t is given by x=t3/3 where x is in meters and t in second. The work done by the force in first two seconds is:
  • 1600 joule
  • 160 joule
  • 16 joule
  • 1.6 joule
The work done by the frictional force on a surface in drawing a circle of radius r on the surface by a pencil of negligible mass with a normal pressing force N (coefficient of friction μk ) is : 
  • 4πr2μKN
  • 2πr2μKN
  • 2πrμKN
  • Zero
A bead is free to slide down a smooth wire tightly stretched between points A and B on a verticle circle of radius R. If the bead starts from rest at 'A', the highest point on the circle, its velocity when it arrives at B is

298025.png
  • 2gR
  • 2gRcosθ
  • 2Rg
  • None of the above
A bob hangs from a rigid support by an inextensible string of length . If it is displaced through a distance (from the lowest position) keeping the string straight, & then released. The speed of the bob at the lowest position is:
293402.png
  • g
  • 3g
  • 2g
  • 5g
A ball of mass 3 kg collides with a wall with velocity 10m/sec at an angle of 30 with the wall and after collision reflects at the same angle with the same speed. The change in momentum of ball in MKS unit is-
  • 20
  • 30
  • 15
  • 45
Two equal masses are attached to the two ends of a spring of spring constant k. The masses are pulled symmetrically to stretch the spring by a length x over its natural length. The work done by the spring on each mass during the pulling is
  • 12kx2
  • 12kx2
  • 14kx2
  • 14kx2
The velocity of a bus, moving on a smooth road, is increased from 8 m/s to 32 m/s in 120s. During this process, the potential energy of the bus
  • Does not change
  • Becomes twice that of initial potential energy
  • Becomes four times that of initial potential energy
  • Becomes sixteen times that of initial potential energy
Two bodies P and Q of equal masses are kept at heights x and 4x respectively. What will be the ratio of their potential energies?
  • 1:8
  • 4:1
  • 1:4
  • 8:1
An object of mass 500 g falls from a height of 2m. If g=9.8m/s2, what is its kinetic energy just before touching the ground?
  • Zero
  • 19.6 J
  • 9.8 J
  • 9800 J
What is work done in holding a body of mass 20 kg at a height of 2 m above the ground? (g=10 m/s2)
  • 40 J
  • 400 J
  • 10 J
  • Zero
Find out work done by applied force to slowly extend the spring from x to 2x.
  • 12kx2
  • 32kx2
  • 52kx2
  • 72kx2
Initially spring is relaxed. A person starts pulling the spring by applying  a variable force F. Find out the work done by F to stretch it slowly to a distance by x.
302034_5fcdefb9c35d4923bfff458326778809.png
  • Kx21
  • Kx22
  • Kx24
  • Kx28
How fast should a girl of 40 kg run so that her kinetic energy is 320J?
  • 64 m/s
  • 8 m/s
  • 16 m/s
  • 4 m/s
Which one of the following possesses both kinetic and potential energies?
  • A man walking on the road
  • A man climbing a hill
  • A man lying on his bed
  • A man running in the garden.
A wound watch spring has ______ energy.
  • Mechanical
  • Kinetic
  • Potential
  • Kinetic and potential
If the speed of a motor car becomes six times, then the kinetic energy becomes
  • 6 times
  • 36 times
  • 12 times
  • 24 times
Asha lifts a doll from the floor and places it on a table. If the weight of the doll is known, what else does one need to know in order to calculate the work Asha has done on the doll?
  • the time required
  • the height of the table
  • the power she could deliver
  • cost of the doll or the table
The spring of the winding knob of a watch has
  • mechanical energy
  • only kinetic energy
  • only potential energy
  • kinetic or potential energy
You lift a suitcase from the floor and keep it on the table. The work done by you on the suitcase depends on
  • the path taken by the suitcase
  • your weight
  • the weight of the suitcase
  • the time taken by you in doing so
The work done in lifting 1 kg mass to a height of 9.8 m is about
  • 1 J
  • 9.8 J
  • (9.8)2J
  • 1(9.8)2J
A car is moving at 100 km/h. If the mass of the car is 950 kg, Its kinetic energy is:
  • 367 MJ
  • 0.367 MJ
  • 3.67 MJ
  • 3.67 J
A girl weighing 50 kg makes a high jump of 1.2 m.What is her kinetic energy at the highest point? (g=10ms2)
  • 6000 J
  • 600 J
  • 60 J
  • Zero
The kinetic energy of a body is increased by increasing its:
  • Mass
  • Weight
  • Velocity
  • Potential energy
The moon revolves around the earth because the earth exerts a radial force on the moon. Does  the earth perform work on the moon?
  • no
  • yes, sometimes
  • yes, always
  • cannot be decided
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