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Work Power and Energy

505 Questions Start Allen Test
All Exams Allen Objective Errorless
AMU PMT 2009 Q151 Errorless Conservation of Energy and Momentum MCQ
A ball is projected vertically upwards with a certain initial speed. Another ball of the same mass is projected at an angle of $60^{\circ}$ with the vertical with the same initial speed. At highest points of their journey, the ratio of their potential energies will be
A.
1:1
B.
2:1
C.
3:2
D.
4:1
EAMCET 2009 Q152 Errorless Conservation of Energy and Momentum MCQ
A bullet of mass 0.02 kg travelling horizontally with velocity $250 \, ms^{-1}$ strikes a block of wood of mass 0.23 kg which rests on a rough horizontal surface. After the impact, the block and bullet move together and come to rest after travelling a distance of 40m. The coefficient of sliding friction of the rough surface is ( $g = 9.8 \, ms^{-2}$ )
A.
0.75
B.
0.61
C.
0.51
D.
0.30
EAMCET 2009 Q153 Errorless POWER MCQ
A motor of power $p_{0}$ is used to deliver water at a certain rate through a given horizontal pipe. To increase the rate of flow of water through the same pipe n times, the power of the motor is increased to $p_{1}$ . The ratio of $p_{1}$ to $p_{0}$ is
A.
n:1
B.
$n^{2}:1$
C.
$n^{3}:1$
D.
$n^{4}:1$
IIT-JEE 2009 Q154 Errorless Elastic and Inelastic Collision MCQ
Three objects A, B and C are kept in a straight line on a frictionless horizontal surface. These have masses m, 2m and m, respectively. The object A moves towards B with a speed 9 m/s and makes an elastic collision with it. Thereafter, B makes completely inelastic collision with C. All motions occur on the same straight line. Find the final speed (in m/s) of the object C
A.
3 m/s
B.
4 m/s
C.
5 m/s
D.
1 m/s
IIT-JEE 2009 Q155 Errorless Critical Thinking MCQ
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 $g = 10 \, m/s^{2}$ , find the work done (in joules) by the string on the block of mass 0.36 kg during the first second after the system is released from rest
A.
6 Joule
B.
5 Joule
C.
8 Joule
D.
2 Joule
IIT-JEE 2009 Q156 Errorless Critical Thinking MCQ
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
A.
4
B.
3
C.
2
D.
1
Kerala PET 2009 Q157 Errorless Graphical Questions MCQ
A particle is acted upon by a force F which varies with position x as shown in figure. If the particle at x = 0 has kinetic energy of 25 J, then the kinetic energy of the particle at $x = 16m$ is
A.
45 J
B.
30 J
C.
70 J
D.
135 J
E.
20 J
KCET 2009 Q158 Errorless Graphical Questions MCQ
The work done by a force acting on a body is as shown in the graph. The total work done in covering an initial distance of 20 m is
A.
225 J
B.
200 J
C.
400 J
D.
175 J
WB-JEE 2009 Q159 Errorless Graphical Questions MCQ
The force $F$ acting on a particle moving in a straight line is shown in figure. What is the work done by the force on the particle in the $1^{\text{st}}$ meter of the trajectory $x(\mathrm{in} \mathrm{m}) \longrightarrow$
A.
5 J
B.
10 J
C.
15 J
D.
2.5 J
AIEEE 2009 Q160 Errorless Graphical Questions MCQ
Consider a rubber ball freely falling from a height h=4.9m onto a horizontal elastic plate. Assume that the duration of collision is negligible and the collision with the plate is totally elastic. Then the velocity as a function of time and the height as a function of time will be
A.

B.

C.

D.

DUMET 2009 Q161 Errorless Self Evaluation Test MCQ
A ball moves in a frictionless inclined table without slipping. The work done by the table surface on the ball is
A.
Positive
B.
Negative
C.
Zero
D.
None of these
AMU PMT 2009 Q162 Errorless Self Evaluation Test MCQ
Identify the wrong statement
A.
A body can have momentum without energy
B.
A body can have energy without momentum
C.
The momentum is conserved in an elastic collision
D.
Kinetic energy is not conserved in an inelastic collision
MP PET 2009 Q163 Errorless Self Evaluation Test MCQ
A neutron travelling with a velocity v and K.E. E collides perfectly elastically head on with the nucleus of an atom of mass number A at rest. The fraction of total energy retained by neutron is
A.
$\left(\frac{A-1}{A+1}\right)^{2}$
B.
$\left(\frac{A+1}{A-1}\right)^{2}$
C.
$\left(\frac{A-1}{A}\right)^{2}$
D.
$\left(\frac{A+1}{A}\right)^{2}$
WB-JEE 2008 Q164 Errorless Work Done by Variable Force MCQ
A wire is stretched under a force. If the wire suddenly snaps the temperature of the wire
A.
Remains the same
B.
Decreases
C.
Increases
D.
First decreases then increases
Kerala PET 2008 Q165 Errorless Conservation of Energy and Momentum MCQ
Two bodies A and B have masses 20 kg and 5 kg respectively. Each one is acted upon by a force of 4 kg wt. If they acquire the same kinetic energy in times $t_{A}$ and $t_{B}$ , then the ratio $\frac{t_{A}}{t_{B}}$ is
A.
1/2
B.
2
C.
2/5
D.
5/6
E.
1/5
Kerala PET 2008 Q166 Errorless Conservation of Energy and Momentum MCQ
A spring gun of spring constant 90 N/cm is compressed 12 cm by a ball of mass 16 g. If the trigger is pulled, the velocity of the ball is
A.
$50 \, ms^{-1}$
B.
$9 \, ms^{-1}$
C.
$40 \, ms^{-1}$
D.
$60 \, ms^{-1}$
E.
$90 \, ms^{-1}$
Kerala PET 2008 Q167 Errorless Conservation of Energy and Momentum MCQ
A bullet of mass 0.05 kg moving with a speed of $80 \, ms^{-1}$ enters a wooden block and is stopped after a distance of 0.40 m. The average resistive force exerted by the block on the bullet is
A.
300 N
B.
20 N
C.
400 N
D.
40 N
E.
200 N
AIEEE 2008 Q168 Errorless Conservation of Energy and Momentum MCQ
An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range
A.
$2 \times 10^{5}$ J ā€“ $3 \times 10^{5}$ J
B.
20,000 J ā€“ 50,000 J
C.
2,000 J ā€“ 5,000 J
D.
200 J ā€“ 500 J
CBSE PMT 2008 Q169 Errorless POWER MCQ
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional forces are 10% of energy. How much power is generated by the turbine ( $g=10\ m/s^{2}$ )
A.
12.3 kW
B.
7.0 kW
C.
8.1 kW
D.
10.2 kW
Odisha JEE 2008 Q170 Errorless Perfectly Inelastic Collision MCQ
Two identical mass $M$ moving with velocity $u_{1}$ and $u_{2}$ collide perfectly inelastically. The loss in energy is
A.
$\frac{M}{2}(u_2 - u_1)^2$
B.
$\frac{M}{2}(u_1 - u_2)^2$
C.
$\frac{M}{4}(u_1 - u_2)^2$
D.
$\frac{M}{4}(u_2 - u_1)^2$
CBSE PMT 2008 Q171 Errorless Critical Thinking MCQ
A shell of mass 200 gm is ejected from a gun of mass 4kg by an explosion that generates 1.05 kJ of energy. The initial velocity of the shell is
A.
$40 \, ms^{-1}$
B.
$120 \, m^{-1}$
C.
$100 \, ms^{-1}$
D.
$80 \, ms^{-1}$
AIIMS 2008 Q172 Errorless Assertion and Reason MCQ
Assertion : A quick collision between two bodies is more violent than slow collision, even when initial and final velocities are identical. Reason : The rate of change of momentum determines that force is small or large.
A.
If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.
If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.
If assertion is true but reason is false.
D.
If the assertion and reason both are false.
E.
If assertion is false but reason is true.
Kerala PMT 2007 Q173 Errorless Work Done by Constant Force MCQ
A man pushes a wall and fails to displace it. He does
A.
Negative work
B.
Positive but not maximum work
C.
No work at all
D.
Maximum work
Kerala PET 2007 Q174 Errorless Work Done by Variable Force MCQ
A rod AB of mass 10kg and length 4m rests on a horizontal floor with end A fixed so as to rotate it in vertical plane about perpendicular axis passing through A. If the work done on the rod is 100J, the height to which the end B be raised vertically above the floor is
A.
1.5 m
B.
2.0 m
C.
1.0 m
D.
2.5 m
AIEEE 2007 Q175 Errorless Conservation of Energy and Momentum MCQ
A 2 kg block slides on a horizontal floor with a speed of 4 m/s. It strikes a uncompressed spring, and compresses it till the block is motionless. The kinetic friction force is 15 N and spring constant is 10,000 N/m. The spring compresses by
A.
5.5 cm
B.
2.5 cm
C.
11.0 cm
D.
8.5 cm