JEE Questions for Physics Work Energy And Power Quiz 15 - MCQExams.com

This question has Statement I and Statement II, of the four choices given after the statements, choose the one that best describes the two statements.
Physics-Work Energy and Power-98589.png
  • Statement I is correct, Statement II is correct, and Statement II is the correct explanation of Statement I
  • Statement I is correct, Statement II is correct, but Statement II is incorrect explanation of Statement I
  • Statement I is correct, Statement II is incorrect
  • Statement I is incorrect, Statement II is correct
P and Q are two identical masses at rest suspended by an inextensible string passing over a smooth frictionless pulley. Mass P is given a downward push with a speed v as shown in fig. It collides with the floor and rebounds. What happens immediately after collision ?
Physics-Work Energy and Power-98591.png
  • P and Q both move upwards with equal speeds
  • P and Q both move upwards with different speeds
  • P moves upwards and Q moves downwards with equal speeds
  • Both P and Q are at rest.

Physics-Work Energy and Power-98592.png
  • 2
  • 8
  • 6
  • 4
Two identical blocks A and B, each of mass m resting on smooth floor are connected by a light spring of natural length L and spring constant K, with the spring in its natural length. A third identical block of mass m, moving with a speed v along the line joining A and B collides with A. The maximum compression in the spring is

  • Physics-Work Energy and Power-98594.png
  • 2)
    Physics-Work Energy and Power-98595.png

  • Physics-Work Energy and Power-98596.png

  • Physics-Work Energy and Power-98597.png
A ball of mass 5 kg is standing on a plane with initial velocity of 10 m/s. If co–efficient of friction between surface and ball is 1/2, then before stopping it will describe...... (g = 10 m/s2)
  • 12.5 m
  • 5 m
  • 7.5 m
  • 10 m
A spring of spring constant 103 N/m is stretched initially 4cm from the unstretched position. How much the work required to stretched it further by another 5 cm?
  • 6.5 NM
  • 2.5 NM
  • 3.25 NM
  • 6.75 NM
A body of mass 6 kg is under a force, which causes a displacement in it given by S = 2t3/3 (in m). Find the work done by the force in first one seconds.
  • 2 J
  • 3.8 J
  • 5.2 J
  • 24 J
A uniform chain of length 2m is kept on a table such that a length of 50cm hangs freely from the edge of the table. The total mass of the chain is 5kg. What is the work done in pulling the entire chain on the table. (g = 10 m\s2)
  • 7.2 J
  • 3 J
  • 4.6 J
  • 120 J
A cord is used to lower vertically a block of mass M by a distance d with constant down-word acceleration 9/2. Work done by the cord on the block is
  • – Mgd/2
  • Mgd/4
  • –3Mgd/4
  • Mgd
A uniform chain of length L and mass M is lying on a smooth table and (1/4)th of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on to the table is
  • MgL
  • MgL/9
  • MgL/18
  • MgL/32
An open knife edge of mass m is dropped from a height h on a wooden floor. If the blade penetrates upto the depth d into the wood, the average resistance offered by the wood to the knife edge is,
  • mg
  • 2)
    Physics-Work Energy and Power-98605.png

  • Physics-Work Energy and Power-98606.png

  • Physics-Work Energy and Power-98607.png
Velocity time graph of a particle of mass 2kg moving in a straight line is as shown in figure. Wrok done by all forces on the particle is
Physics-Work Energy and Power-98609.png
  • 400 J
  • –400 J
  • –200 J
  • 200 J
A mass of M kg is suspended by a weight-less string, the horizontal force that is required to displace it until the string makes an angle of 60o with the intial varticale direction is

  • Physics-Work Energy and Power-98611.png
  • 2)
    Physics-Work Energy and Power-98612.png

  • Physics-Work Energy and Power-98613.png

  • Physics-Work Energy and Power-98614.png
A force F = Ay2 + By + C acts on a body in the y-direction. The work done by this force during a displacement from y = –a to y = a is

  • Physics-Work Energy and Power-98616.png
  • 2)
    Physics-Work Energy and Power-98617.png

  • Physics-Work Energy and Power-98618.png
  • None of these
A body having a mass of 0.5 kg slips along the wall of a semispherical smooth surface of radius 20 cm shown in figure.What is the velocity of body at the bottom of the surface ? (g = 10 m/s2)
Physics-Work Energy and Power-98620.png

  • Physics-Work Energy and Power-98621.png
  • 2 m/s

  • Physics-Work Energy and Power-98622.png
  • 4 m/s
A particle is placed at the origin and a force F = kx is acting on it (Where K is positive constant) If Ucos = 0, which one of the following graph of U(x) versus x. (where U is the potential energy function)

  • Physics-Work Energy and Power-98624.png
  • 2)
    Physics-Work Energy and Power-98625.png

  • Physics-Work Energy and Power-98626.png

  • Physics-Work Energy and Power-98627.png
The potential energy of a projectile at its highest point is (1/2)th the value of its initial kinetic energy. Therefore its angle of projection is ......
  • 30o
  • 45o
  • 60o
  • 75o
Two bodies P and Q have masses 5 kg and 20 kg respectively. Each one is acted upon by a force of 4 N. If they acquire the same kinetic energy in times tp and tq then the ratio tp/tq = ..........
  • 1/2
  • 2
  • 2/5
  • 5/6

Physics-Work Energy and Power-98631.png

  • Physics-Work Energy and Power-98632.png
  • 2)
    Physics-Work Energy and Power-98633.png

  • Physics-Work Energy and Power-98634.png

  • Physics-Work Energy and Power-98635.png
A rifle bullet loss (1/10)th of its velocity in passing through a plank. The least number of such planks required just to stop the bullent is
  • 5
  • 10
  • 11
  • 20
A frictionless track 12345 ends in a circular loop of radius R. A body slids down the track from point 1 Which is 6 cm. Maximum value of R for the body to successfully complete the loop is
Physics-Work Energy and Power-98638.png
  • 6 cm
  • 15/4 cm
  • 5/12 cm
  • 12/5 cm
A bomb of 12 kg divedes in two parts whose ratio of masses is 1:4. If kinetic energy of smaller part is 288 J, then momentum of bigger part in kgm/sec will be
  • 48
  • 72
  • 108
  • Data is incomplete
An ice-cream has a marked value of 700 kcal. How many kilo-watt-hour of energy will it deliver to the body as it is digested (J = 4.2 J/cal)
  • 0.81 kwh
  • 0.90 kwh
  • 1.11 kwh
  • 0.71 kwh
A spherical ball of mass 15 kg stationary at the top of a hill of height 82m. It slides down a smooth surface to the ground, then climbs up another hill of height 32m and finally slides down to horizontal base at a height of 10 m above the ground. The velocity attained by the ball is
Physics-Work Energy and Power-98642.png

  • Physics-Work Energy and Power-98643.png
  • 2)
    Physics-Work Energy and Power-98644.png

  • Physics-Work Energy and Power-98645.png

  • Physics-Work Energy and Power-98646.png
A bomb of mass 10 kg explodes into 2 pieces of mass 4 kg and 6 kg. The velocity of mass 4 kg is 1.5 m/s, the K.E. of mass 6 kg is .......
  • 3.84 J
  • 9.6 J
  • 3.00 J
  • 2.5 J
A bomb of mass 3.0 kg explodes in air into two pieces of masses 2.0 kg and 1.0kg. The smaller mass goes at a speed of 80m/s. The total energy imparted to the two fragments is
  • 1.07 KJ
  • 2.14 KJ
  • 2.4 KJ
  • 4.8 KJ
The potential energy of a conservative system is given by U(X) = (x2 – 5x) J. Then the equilibrium position is at....... (where x in m)
  • x = 1.5 m
  • x = 2m
  • x = 2.5 m
  • x = 5 m
A nucleus at rest splits into two nuclear parts having same density and radii in the ratio 1:2. Their velocites are in the ratio
  • 2:1
  • 4:1
  • 6:1
  • 8:1
A single conservative force F(x) acts on a 2.5 kg particle that moves along the x–axis. The potential energy U(x) is given by U(x) = (10 + (x – 4)2) where x is in meter. At x = 6.0 m the particle has kinetic energy of 20 J. What is the mechanical energy of the system ?
  • 34 J
  • 45 J
  • 48 J
  • 49 J
From an automatic gun a man fires 240 bullet per minute with a speed of 360 km/h. If each weighs 20 g, the power of the gun is
  • 400 W
  • 300 W
  • 150 W
  • 600 W
A body is moved along a straight line by a machine delivering a constant power. The velocity gained by the body in time t is proportional to.....

  • Physics-Work Energy and Power-98653.png
  • 2)
    Physics-Work Energy and Power-98654.png

  • Physics-Work Energy and Power-98655.png

  • Physics-Work Energy and Power-98656.png
A particle of mass m moving with horizontal speed 6 m/s as shown in figure. If m << M then for one dimensional elastic collision, the speed of lighter particle after collision will be
Physics-Work Energy and Power-98658.png
  • 1 m/s in original direction.
  • 2 m/s opposite to the original direction.
  • 1 m/s opposite to the original direction.
  • 2 m/s in original direction.
Three objects A, B and C are kept in a straight line on a frictionless horizontal surface. These have masses m, 2m and m respectivelly. The object A moves towards B with a speed 9 m/s and makes an elastic collision with it. Thereafter, B makes compelety inelastic collision with C. All motion occur on the same straight line. Find final speed of the object C
Physics-Work Energy and Power-98660.png
  • 3 m/s
  • 4 m/s
  • 5 m/s
  • 1 m/s
A metal ball of mass 2 kg moving with a velocity of 36 km/h has a head on collision with a stationary ball of mass 3 kg. If after the collision, the two balls move togather, the loss in kinetic energy due to collision is
  • 40 J
  • 60 J
  • 100 J
  • 140 J
A mass of 100g strikes the wall speed 5 m/s at an angle as shown in figure and is rebounds with the same speed. If the contact time is 5 × 10–3 sec, what is the force applied on the mass by the wall
Physics-Work Energy and Power-98663.png

  • Physics-Work Energy and Power-98664.png
  • 100 N to right

  • Physics-Work Energy and Power-98665.png
  • 100 N to left
A bullet of mass m moving with velocity v strikes a block of mass M at rest and gets embedded into it. The kinetic energy of the composite block will be

  • Physics-Work Energy and Power-98667.png
  • 2)
    Physics-Work Energy and Power-98668.png

  • Physics-Work Energy and Power-98669.png

  • Physics-Work Energy and Power-98670.png
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, repectively, 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-98672.png
  • 1
  • 2
  • 3
  • 4
Two springs A and B are identical but A is harder than B(kA > kB ). Let WA and WB represent the work done when the springs are stretched through the same distance and W’A and W’B are the work done when these are stretched by equal forces, then which of the following is true
  • WA > WB and W’A = W’B
  • WA > WB and W’A < W’B
  • WA > WB and W’A > W’B
  • WA < WB and W’A < W’B
A car of mass \'m\' is driven with acceleration \'a\' along a straight level and against a constant external resistive force \'R\'. When the velocity of the car is \'V\' the rate at which the engine of the car is doing work will be
  • RV
  • maV
  • (R + ma)V
  • (ma – R)V
A vertical spring with force constant K is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance d. The net work done in the process is
Physics-Work Energy and Power-98676.png

  • Physics-Work Energy and Power-98677.png
  • 2)
    Physics-Work Energy and Power-98678.png

  • Physics-Work Energy and Power-98679.png

  • Physics-Work Energy and Power-98680.png
A frictionless track ABCDE ends in a circular loop of radius R. A body slides down the track from point A which is at a height h = 5 cm. Maximum value of R for the body to successfully complete the loop is
Physics-Work Energy and Power-98681.png
  • 5 cm
  • 2)
    Physics-Work Energy and Power-98682.png

  • Physics-Work Energy and Power-98683.png
  • 2 cm
A running man has half the kinetic energy of that of a body of half of his mass. The man speeds up by 1 m/s so as to have same K.E. as that of the boy. The original speed of the man will be

  • Physics-Work Energy and Power-98685.png
  • 2)
    Physics-Work Energy and Power-98686.png

  • Physics-Work Energy and Power-98687.png

  • Physics-Work Energy and Power-98688.png
A canon ball is fired with a velocity 200 m/sec at an angle of 60° with the horizontal. At the highest point of its flight it explodes into 3 equal fragments, one going vertically upwards with a velocity 100 m/sec, the second one falling vertically downwards with a velocity 100 m/sec. The third fragment will be moving with a velocity
  • 100 m/s in the horizontal direction
  • 300 m/s in the horizontal direction
  • 300 m/s in a direction making an angle of 60° with the horizontal
  • 200 m/s in a direction making an angle of 60° with the horizontal
A billiards player hits a stationary ball by an identical ball to pocket the target ball in a corner pocket that is at an angle of 35° with respect to the direction of motion of the first ball. Assuming the collision as elastic and that friction and rotational motion are not important, the angle made by the target ball with respect to the incoming balls is
  • 35o
  • 50o
  • 55o
  • 60o
A ball hits the floor and rebounds after inelastic collision. In this case
  • The momentum of the ball just after the collision is the same as that just before collision
  • The mechanical energy of the ball remains the same in the collision
  • The total momentum of the ball and the earth is conserved
  • The total energy of the ball and the earth is conserved
Two identical cylindrical vessels with their bases at same level each contains a liquid of density ρ. The height of the liquid in one vessel is h1 and that in the other vessel is h2. The area of either base is A. The work done by gravity in equalizing the levels when the two vessels are connected, is
  • (h1 – h2)gρ
  • (h1 – h2)gAρ

  • Physics-Work Energy and Power-98695.png

  • Physics-Work Energy and Power-98696.png
Two identical blocks A and B, each of mass \'m\' resting on smooth floor are connected by a light spring of natural length L and spring constant K, with the spring at its natural length. A third identical block (mass m) moving with a speed v along the line joining A and B collides with A. The maximum compression in the

  • Physics-Work Energy and Power-98698.png
  • 2)
    Physics-Work Energy and Power-98699.png

  • Physics-Work Energy and Power-98700.png

  • Physics-Work Energy and Power-98701.png
A bag (mass M) hangs by a long thread and a bullet (mass m) comes horizontally with velocity v and gets caught in the bag. Then for the combined (bag + bullet) system

  • Physics-Work Energy and Power-98703.png
  • 2)
    Physics-Work Energy and Power-98704.png

  • Physics-Work Energy and Power-98705.png

  • Physics-Work Energy and Power-98706.png
The relationship between force and position is shown in the figure given (in one dimensional case). The work done by the force in displacing a body from x = 1 cm to x = 5cm is
Physics-Work Energy and Power-98708.png
  • 20 ergs
  • 60 ergs
  • 70 ergs
  • 700 ergs
The pointer reading v/s load graph for a spring balance is as given in the figure. The spring constant is
Physics-Work Energy and Power-98710.png
  • 0.1 kg/cm
  • 5 kg/cm
  • 0.3 kg/cm
  • 1 kg/cm
0:0:1


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