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Work, Power & Energy

238 Questions Start Errorless Test
All Exams Allen Advance Errorless
CBSE PMT (Mains) 2012 Q126 Errorless 4. Power MCQ
A car of mass m starts from rest and accelerates so that instantaneous power delivered to the car has a constant magnitude $P_{0}$ . The instantaneous velocity of this car is proportional to
A.
$t^{2}P_{0}$
B.
$t^{1/2}$
C.
$t^{-1/2}$
D.
$\frac{t}{\sqrt{m}}$
Kerala PET 2012 Q127 Errorless 8. Graphical Questions MCQ
The shape of the curve representing the relation between the speed and kinetic energy of a moving object is
A.
Parabola
B.
Ellipse
C.
Straight line with positive slope
D.
Straight line with negative slope
E.
Exponential
Odisha JEE 2011, 12 Q128 Errorless 1. Work Done by Constant Force MCQ
A block of mass 5kg is resting on a smooth surface. At what angle a force of 20N be acted on the body so that it will acquired a kinetic energy of 40J after moving 4m
A.
30Ā°
B.
45Ā°
C.
60Ā°
D.
120Ā°
CBSE PMT (Pre.) 2011 Q129 Errorless 4. Power MCQ
A body projected vertically from the earth reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force is greatest
A.
At the instant just after the body is projected
B.
At the highest position of the body
C.
At the instant just before the body hits the earth
D.
It remains constant all through
Kerala PET 2011 Q130 Errorless 5. Elastic and Inelastic Collision MCQ
A ball dropped from a height of 2m rebounds to a height of 1.5m after hitting the ground. Then the percentage of energy lost is
A.
25
B.
30
C.
50
D.
100
E.
200
Odisha JEE 2011 Q131 Errorless 5. Elastic and Inelastic Collision MCQ
Two masses of 0.25kg each moves towards each other with speed $3ms^{-1}$ and $1ms^{-1}$ collide and stick together. Find the final velocity
A.
$0.5ms^{-1}$
B.
$2ms^{-1}$
C.
$1ms^{-1}$
D.
$0.25ms^{-1}$
IIT-JEE 2011 Q132 Errorless 9. JEE Section Numerical
A block of mass 0.18 kg is attached to a spring of force-constant 2 N/m. The coefficient of friction between the block and the floor is 0.1. Initially the block is at rest and the spring is un-stretched. An impulse is given to the block as shown in the figure. The block slides a distance of 0.06 m and comes to rest for the first time. The initial velocity of the block in m/s is V = N/10. Then N is
AIEEE 2010 Q133 Errorless 2. Work Done by Variable Force MCQ
The potential energy function for the force between two atoms in a diatomic molecule is approximately given by $U(x)=\frac{a}{x^{12}}-\frac{b}{x^{6}}$ , where a and b are constants and x is the distance between the atoms. If the dissociation energy of the molecule is $D=[U(x=\infty)-U_{\mathrm{at equilibrium}}]$ , D is
A.
$\frac{b^{2}}{6a}$
B.
$\frac{b^{2}}{2a}$
C.
$\frac{b^{2}}{12a}$
D.
$\frac{b^{2}}{4a}$
J & K CET 2010 Q134 Errorless 3. Conservation of Energy and Momentum MCQ
The energy associated with one gram of mass is
A.
$9 \times 10^{-13} J$
B.
$9 \times 10^{-16} J$
C.
$9 \times 10^{13} J$
D.
$9 \times 10^{16} J$
MP PET 2010 Q135 Errorless 4. Power MCQ
A body of mass $M$ is moving with a uniform speed of $10m / s$ on frictionless surface under the influence of two forces $F_{1}$ and $F_{2}$ . The net power of the system is
A.
$10F_{1}F_{2}M$
B.
$10(F_{1} + F_{2})M$
C.
$(F_{1} + F_{2})M$
D.
Zero
CBSE PMT 2010 Q136 Errorless 4. Power MCQ
An engine pumps water through a hose pipe. Water passes through the pipe and leaves it with a velocity of 2 m/s. The mass per unit length of water in the pipe is 100 kg/m. What is the power of the engine
A.
800 W
B.
400 W
C.
200 W
D.
100 W
CBSE PMT 2010 Q137 Errorless 5. Elastic and Inelastic Collision MCQ
A ball moving with velocity 2 m/s. collides head on with another stationary ball of double the mass. If the coefficient of restitution is 0.5, then their velocities (in m/s.) after collision will be
A.
0, 2
B.
0, 1
C.
1, 1
D.
1, 0.5
Odisha JEE 2010 Q138 Errorless 5. Elastic and Inelastic Collision MCQ
In an inelastic collision
A.
Only momentum is conserved
B.
Only kinetic energy is conserved
C.
Neither momentum nor kinetic energy is conserved
D.
Both momentum and kinetic energy are conserved
J & K CET 2010 Q139 Errorless 5. Elastic and Inelastic Collision MCQ
Three identical spherical balls $A, B$ and $C$ are placed on a table as shown in the figure along a straight line. $B$ and $C$ are at rest initially. The ball A hits B head on with a speed of $10 \, m \, s^{-1}$ . Then after all collisions (assumed to be elastic) A and B are brought to rest and C takes off with a velocity of
A.
$5 \, m \, s^{-1}$
B.
$10 \, m \, s^{-1}$
C.
$2.5 \, m \, s^{-1}$
D.
$7.5 \, m \, s^{-1}$
Kerala PMT 2010 Q140 Errorless 7. Critical Thinking MCQ
The potential energy of a conservative system is given by $V(x) = (x^{2} - 3x)$ joule. Then its equilibrium position is at
A.
x = 1.5 m
B.
x = 2 m
C.
x = 2.5 m
D.
x = 3 m
E.
x = 0.33 m
IIT-JEE 2010 Q141 Errorless 8. Graphical Questions MCQ
A block of mass 2 kg is free to move along the x-axis. It is at rest and from t = 0 onwards it is subjected to a time-dependent force $F(t)$ in the x-direction. The force $F(t)$ varies with t as shown in the figure. The kinetic energy of the block after 4.5 seconds is
A.
4.50 J
B.
7.50 J
C.
5.06 J
D.
14.06 J
IIT-JEE 2010 Q142 Errorless 9. JEE Section MSQ
A point mass of 1 kg collides with a stationary point mass of 5 kg. After their collision, the 1 kg mass reverses its direction and moves with a speed of $2ms^{-1}$ . Which of the following statement(s) is (are) correct for the system of these two masses
A.
Total momentum of the system is 3 kg ms $^{-1}$
B.
Momentum of 5 kg mass after collision is 4 kg ms $^{-1}$
C.
Kinetic energy of the centre of mass is 0.75 J
D.
Total kinetic energy of the system is 4 J
AIEEE 2010 Q143 Errorless 9. JEE Section MCQ
Statement-1 : Two particles moving in the same direction do not lose all their energy in a completely inelastic collision. Statement-2 : Principle of conservation of momentum holds true for all kinds of collisions.
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.
CBSE PMT 2009 Q144 Errorless 1. Work Done by Constant Force MCQ
A body of mass 1 kg is thrown upwards with a velocity 20 m/s. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction ( $g = 10 \, m/s^{2}$ )
A.
20 J
B.
30 J
C.
40 J
D.
10 J
EAMCET 2009 Q145 Errorless 3. 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 Q146 Errorless 4. 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 Q147 Errorless 5. 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 image.png
A.
3 m/s
B.
4 m/s
C.
5 m/s
D.
1 m/s
Kerala PET 2009 Q148 Errorless 8. 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 = 16 m is
A.
$45\mathrm{J}$
B.
$30\mathrm{J}$
C.
70 J
D.
135 J
E.
20 J
KCET 2009 Q149 Errorless 8. 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 Q150 Errorless 8. 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
A.
5 J
B.
10 J
C.
15 J
D.
2.5 J