JEE Questions for Physics Work Energy And Power Quiz 3 - MCQExams.com

A 10 kg object collides with stationary 5 kg object and after collision they stick together and move forward with velocity 4 ms-1. What is the velocity with which the 10 kg object hit the second one ?
  • 4 ms-1
  • 6 ms-1
  • 10 ms-1
  • 12 ms-1
A body of mass m1 collides elastically with another body of mass m2 at rest. If the velocity of m1 after collision becomes 2/3 times its initial velocity, the ratio of their masses is
  • 1 : 5
  • 5 : 1
  • 5 : 2
  • 2 : 5
A 20 kg of ball moving with a velocity 6 ms -1 collides with a 30 kg of ball initially at rest. If both of them coalesce, then the final velocity of the combined mass is
  • 6 ms -1
  • 5 ms -1
  • 3.6 ms -1
  • 2.4 ms -1
  • 1.2 ms -1
A neutron moving with velocity v collides with a stationary α–particle. The velocity of the neutron after the collision is

  • Physics-Work Energy and Power-97489.png
  • 2)
    Physics-Work Energy and Power-97490.png

  • Physics-Work Energy and Power-97491.png

  • Physics-Work Energy and Power-97492.png
In a head on elastic collision of a very heavy body moving at v with a light body at rest, velocity of heavy body after collision is
  • v
  • 2v
  • zero
  • v/2

Physics-Work Energy and Power-97494.png
  • p
  • 2)
    Physics-Work Energy and Power-97495.png

  • Physics-Work Energy and Power-97496.png
  • zero
A constant power P is applied to a car starting from rest. If v is the velocity of the car at time t, then
  • v ∝ t
  • 2)
    Physics-Work Energy and Power-97498.png

  • Physics-Work Energy and Power-97499.png

  • Physics-Work Energy and Power-97500.png
Power applied to a particle varies with time as P = (3t2 – 2t +watt,where t is in second. Find the change in its kinetic energy between t = 2s and t = 4s
  • 32J
  • 46J
  • 61J
  • 100J
When a U238 nucleus, originally at rest, decays by emitting an α - particle , say with a speed Vm/sec, the recoil speed of the residual nucleus is (in m /sec.) :
  • –4V/ 234
  • –4V/238
  • 4V/238
  • –V/4
Which of the following is a unit of energy
  • Unit
  • Watt
  • Horse Power
  • None
A ball is released from certain height. It loses 50% of its kinetic energy on striking the ground. It will attain a height again equal to
  • One fourth the initial height
  • Half the initial height
  • Three fourth initial height
  • None of these
A light inextensible string that goes over a smooth fixed pulley as shown in the figure connects two blocks of masses 0.36 kg and 0.72 kg. Taking, g = 10 ms-2, find the work done (in joule) by string on the block of mass 0.36 kg during the first second after the system is released from rest.
Physics-Work Energy and Power-97504.png
  • 8 J
  • 9 J
  • 7 J
  • 0.48 J
If reaction is R and coefficient of friction is µ, what is work done against friction in moving a body by distance d ?
Physics-Work Energy and Power-97506.png

  • Physics-Work Energy and Power-97507.png
  • 2)
    Physics-Work Energy and Power-97508.png

  • Physics-Work Energy and Power-97509.png

  • Physics-Work Energy and Power-97510.png

Physics-Work Energy and Power-97512.png

  • Physics-Work Energy and Power-97513.png
  • 2)
    Physics-Work Energy and Power-97514.png

  • Physics-Work Energy and Power-97515.png

  • Physics-Work Energy and Power-97516.png
A particle of mass m is being circulated on a vertical circle of radius r. If the speed of particle at the highest point be v, then

  • Physics-Work Energy and Power-97518.png
  • 2)
    Physics-Work Energy and Power-97519.png

  • Physics-Work Energy and Power-97520.png

  • Physics-Work Energy and Power-97521.png

Physics-Work Energy and Power-97523.png
  • E
  • 2E

  • Physics-Work Energy and Power-97524.png

  • Physics-Work Energy and Power-97525.png

  • Physics-Work Energy and Power-97526.png
A small roller coaster starts at point A with a speed u on a curved track as shown in the figure. The friction between the roller coaster and the track is negligible and it always remains in contact with the track. The speed of roller coaster at point D on the track will be
Physics-Work Energy and Power-97528.png
  • ( u2 + gh )1/2
  • ( u2 + 2gh )1/2
  • ( u2 + 4gh )1/2
  • u

Physics-Work Energy and Power-97529.png

  • Physics-Work Energy and Power-97530.png
  • 2)
    Physics-Work Energy and Power-97531.png

  • Physics-Work Energy and Power-97532.png
  • 2
A body moving with velocity v has momentum and kinetic energy numerically equal. What is the value of v
  • 2 m/s
  • √2 m/s
  • 1 m/s
  • 0.2 m/s
A running man has the same kinetic energy as that of a boy of half his mass. The man speed up by 2 ms-1 and the boy changes his speed by x ms-1, so that the kinetic energies of the boy and the man are again equal. Then, x in ms-l is

  • Physics-Work Energy and Power-97534.png
  • 2)
    Physics-Work Energy and Power-97535.png

  • Physics-Work Energy and Power-97536.png
  • 2

  • Physics-Work Energy and Power-97537.png
A particle is placed at the origin and a force F = kx is acting on it (where k is positive constant). If U(= 0, the graph of U(x) versus x will be (where U is potential energy function)

  • Physics-Work Energy and Power-97539.png
  • 2)
    Physics-Work Energy and Power-97540.png

  • Physics-Work Energy and Power-97541.png

  • Physics-Work Energy and Power-97542.png
Which of the following graphs shows variation of potential energy (U) with position x

  • Physics-Work Energy and Power-97544.png
  • 2)
    Physics-Work Energy and Power-97545.png

  • Physics-Work Energy and Power-97546.png

  • Physics-Work Energy and Power-97547.png

Physics-Work Energy and Power-97548.png
  • 4
  • 2
  • 1/2
  • 1/4
Statement I: Two particles moving in the same direction do not lose all their energy in a completely inelastic collision.
Statement II: Principle of conservation of momentum holds true for all kinds of collisions.
  • Statement I is correct, Statement II is correct, Statement II is the correct explanation of Statement I
  • Statement I is correct Statement II is correct, Statement II incorrect explanation of Statement I
  • Statement I is incorrect, Statement II is correct
  • Statement I is correct, Statement II is incorrect
Two small particles of equal masses start moving in opposite directions from a point A in a horizontal circular orbit. Their tangential velocities are v and 2v respectively, as shown in the figure. Between collisions, the particles move with constant speeds. After making how many elastic collisions, other than that at A, these two particles will again reach the point A?
Physics-Work Energy and Power-97550.png
  • 4
  • 3
  • 2
  • 1
A body of mass 2 kg moving with a velocity of 3 ms -1 collides head on with a body of mass 1 kg moving in opposite direction with a velocity of 4 ms-1. After collision two bodies stick together and move with a common velocity which in ms -1 is equal to
  • 1/4
  • 1/3
  • 2/3
  • 3/4
In two separate collisions, the coefficient of restitutions e1 and e2 are in the ratio 3 : 1. In the first collision the relative velocity of approach is twice the relative velocity of separation, then the ratio between relative velocity of approach and the relative velocity of separation in the second collision is
  • 1 : 6
  • 2 : 3
  • 3 : 2
  • 6 : 1
A stationary bomb explodes into two parts of masses in the ratio of 1 : 3. If the heavier mass moves with a velocity 4 ms -1 , what is the velocity of lighter part?
  • 12 ms-1 opposite to heavier mass
  • 12 ms-1 in the direction of heavier mass
  • 6 ms-1 opposite to heavier mass
  • 6 ms-1 in the direction of heavier mass
A bullet of mass 20 g and moving with 600 ms-1 collides with a block of mass 4 kg hanging with the string. What is velocity of bullet when it comes out of block if block rises to height 0.2 m after collision?
  • 200 ms-1
  • 150 ms-1
  • 400 ms-1
  • 300 ms-1
For a system to follow the law of conservation of linear momentum during a collision, the condition is
I. total external force acting on the system is zero
II. total external force acting on the system is finite and time of collision is negligible.
III. total internal force acting on the system is zero.
  • Only I
  • Only II
  • Only III
  • Only I & II

Physics-Work Energy and Power-97556.png

  • Physics-Work Energy and Power-97557.png
  • 2)
    Physics-Work Energy and Power-97558.png

  • Physics-Work Energy and Power-97559.png

  • Physics-Work Energy and Power-97560.png
A body of mass m moving with velocity v collides head on another body of mass 2m which is initially at rest. The ratio of kinetic energy of colliding body before and after collision will be
  • 1 : 1
  • 2 : 1
  • 4 : 1
  • 9 : 1
A body of mass 4 kg moving with velocity 12 ms -1 collides with another body of mass 6 kg at rest. If two bodies stick together after collision, then the loss of kinetic energy of system is
  • zero
  • 288 J
  • 172.8 J
  • 144 J
1 kg body explodes into three fragments. The ratio of their masses is 1:1:3. The fragments of same mass move perpendicular to each other with speeds 30 ms -1, while the heavier part remains in the initial direction. The speed of heavier part is

  • Physics-Work Energy and Power-97564.png
  • 10√2 ms -1
  • 20√2 ms -1
  • 30√2 ms -1
The height of the dam, in a hydroelectric power station is 10 m. In order to generate 1 MW of electric power, the mass of water (in kg) that must fall per second on the blades of the turbines is
  • 106
  • 105
  • 103
  • 104
  • 102
A particle is released from a height h. At a certain height, its kinetic energy is two times its potential energy. Height and speed of the particle at that instant are

  • Physics-Work Energy and Power-97567.png
  • 2)
    Physics-Work Energy and Power-97568.png

  • Physics-Work Energy and Power-97569.png

  • Physics-Work Energy and Power-97570.png
A particle is released from a height S. At certain height its kinetic energy is three times its potential energy. The height and speed of the particle at that instant are respectively

  • Physics-Work Energy and Power-97572.png
  • 2)
    Physics-Work Energy and Power-97573.png

  • Physics-Work Energy and Power-97574.png

  • Physics-Work Energy and Power-97575.png

  • Physics-Work Energy and Power-97576.png
The pointer reading vs load graph for a spring balance is shown here. The spring constant is
Physics-Work Energy and Power-97578.png
  • 15 kg f /cm
  • 5 kg f / cm
  • 0.1 kg f /cm
  • 10 kg f / cm
A motor drives a body along a straight line with a constant force.The power P developed by the motor must very with time t as

  • Physics-Work Energy and Power-97580.png
  • 2)
    Physics-Work Energy and Power-97581.png

  • Physics-Work Energy and Power-97582.png

  • Physics-Work Energy and Power-97583.png
An automobile engine of mass m accelerates and a constant power P is applied by the engine. The instantaneous speed of the engine will be

  • Physics-Work Energy and Power-97585.png
  • 2)
    Physics-Work Energy and Power-97586.png

  • Physics-Work Energy and Power-97587.png

  • Physics-Work Energy and Power-97588.png
A missile is released with a velocity less than the escape velocity. The sum of its potential and kinetic energies is
  • negative
  • positive
  • zero
  • cannot say
A body is under the action of two equal and opposite forces, each of 3N. The body is displaced by 2m.The work done is :
  • + 6J
  • – 6J
  • 0
  • none of the above
Fig. shows the top view of two horizontal forces pulling a box along the floor. The work done by each force to displace the box 70 cm along the broken line is
Physics-Work Energy and Power-97590.png
  • 24.74J, 42.4 J
  • 42.4J, 20.75 J
  • 40 J, 24.74 J
  • 42 J, 24 J
A rock weighing 50 N falls from a height of 10 m and sinks 0.5 m into the ground. From energy consideration, the average force f between the rock and the ground as the rock sinks is :
Physics-Work Energy and Power-97592.png
  • 105 N
  • 10.50 N
  • 1050 N
  • 1360 N
The vessels A and B of equal volume and weight are immersed in water to depth h. The vessel A has an opening at the bottom through which water can enter. If the work done in immersing A and B are WA and WB respectively, then:
  • WA = WB
  • WA < WB
  • WA > WB

  • Physics-Work Energy and Power-97594.png
A block of mass 0.5 kg has an initial velocity of 10m/s down an inclined plane of angle 300, the coefficient of friction between the block and the inclined surface is 0.2. The velocity of the block after it travels a distance of 10 m is
Physics-Work Energy and Power-97595.png
  • 17 m/s
  • 13 m/s
  • 24 m/s
  • 8 m/s
An object of mass m is tied to a string of length l and a variable horizontal force is applied on it , which starts at zero and gradually increases (it is pulled extremely slowly so that quilibrium exists at all times) until the string makes an angle Ө with the vertical. Work done by the force F is
Physics-Work Energy and Power-97597.png
  • mgl (1 ‒ sin θ)
  • mgl
  • mgl (1 ‒ cos θ)
  • mgl (1 ‒ tan θ)
A stone of mass m kg is whirled in a vertical circle of radius 20 cm .The difference of the kinetic energies at the lowest and the topmost position is :
  • 4 mg joule
  • 0.4 mg joule
  • 40 mg joule
  • None of these
A ball is allowed to fall down with initial speed v from a height of 10 m. It loses 50 % kinetic energy after striking the floor. It reaches to the same height after collision.What is the value of v ?
  • 28 m/ s
  • 7 m/s
  • 14 m/s
  • it is never possible
A mass of 2 kg rests on an inclined plane of gradient 1 in 8 as shown in fig. The work done in sliding it from the lowest point of the incline to the highest point, if the coefficient of friction is 0.2, is :
Physics-Work Energy and Power-97600.png
  • 192 J
  • 19.2 J
  • 48 J
  • 52 J
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Physics Quiz Questions and Answers