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Work Power and Energy

505 Questions Start Allen Test
All Exams Allen Objective Errorless
CBSE AIPMT 2012 Q126 Objective Medical entrances' gallery MCQ
The potential energy of a particle in a force field is $U = \frac{A}{r^{2}} - \frac{B}{r}$ , where A and B are positive constants and r is the distance of particle from the centre of the field. For stable equilibrium, the distance of the particle is
A.
B/2A
B.
2A/B
C.
A/B
D.
B/A
AIIMS 2012 Q127 Objective Medical entrances' gallery MCQ
The particle of mass 50 kg is at rest. The work done to accelerate it by 20 ms $^{-1}$ in 10 s is
A.
$10^{3}$ J
B.
$10^{4}$ J
C.
$2 \times 10^{3}$ J
D.
$4 \times 10^{4}$ J
BCECE Mains 2012 Q128 Objective Medical entrances' gallery MCQ
The slope of kinetic energy and displacement curve for a particle in motion will be
A.
equal to the acceleration of the particle
B.
directly proportional to the acceleration of the particle
C.
inversely proportional to the acceleration of the particle
D.
None of the above
BHU 2012 Q129 Objective Medical entrances' gallery MCQ
Two masses m and 2m are attached to two ends of an ideal spring as shown in figure. When the spring is in the compressed state, the energy of the spring is 60 J, if the spring is released, then at its natural length,
A.
energy of smaller body will be 20 J
B.
energy of smaller body will be 40 J
C.
energy of smaller body will be 10 J
D.
energy of both the bodies will be same
Odisha JEE 2011, 12 Q130 Errorless 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 Q131 Errorless 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
Odisha JEE 2011 Q132 Errorless Elastic and Inelastic Collision MCQ
Two masses of $0.25\mathrm{kg}$ each moves towards each other with speed $3\mathrm{ms}^{-1}$ and $1\mathrm{ms}^{-1}$ collide and stick together. Find the final velocity
A.
$0.5\mathrm{ms}^{-1}$
B.
$2\mathrm{ms}^{-1}$
C.
$1\mathrm{ms}^{-1}$
D.
$0.25\mathrm{ms}^{-1}$
Kerala PET 2011 Q133 Errorless 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
IIT-JEE 2011 Q134 Errorless Critical Thinking MCQ
A ball of mass 0.2 kg rests on a vertical post of height 5 m. A bullet of mass 0.01 kg, traveling with a velocity V m/s in a horizontal direction, hits the centre of the ball. After the collision, the ball and bullet travel independently. The ball hits the ground at a distance of 20 m and the bullet at a distance of 100 m from the foot of the post. The initial velocity V of the bullet is
A.
250m/s
B.
$250\sqrt{2}$ m/s
C.
400m/s
D.
500m/s
CBSE PMT (Pre.) 2011 Q135 Errorless Self Evaluation Test MCQ
The potential energy of a system increases if work is done
A.
Upon the system by a conservative force
B.
Upon the system by a non-conservative force
C.
By the system against a conservative force
D.
By the system against a non-conservative force
Kerala PMT 2011 Q136 Errorless Self Evaluation Test MCQ
Choose the incorrect statement
A.
No work is done if the displacement is perpendicular to the direction of the applied force
B.
If the angle between the force and displacement vectors is obtuse, then the work done is negative
C.
Frictional force in non-conservative
D.
All the central forces are non-conservative
E.
Kinetic energy is conserved in elastic collision
Kerala PMT 2010 Q137 Errorless Work Done by Constant Force MCQ
Stopping distance of a moving vehicle is directly proportional to
A.
Square of the initial velocity
B.
Square of the initial acceleration
C.
The initial velocity
D.
The initial acceleration
E.
Mass of the vehicle
AIIMS 2010 Q138 Errorless Work Done by Constant Force MCQ
A cord is used to lower vertically a block of mass $M$ by a distance $d$ with constant downward acceleration $\frac{g}{4}$ . Work done by the cord on the block is
A.
$Mg\frac{d}{4}$
B.
$3Mg\frac{d}{4}$
C.
$-3Mg\frac{d}{4}$
D.
$Mgd$
AIEEE 2010 Q139 Errorless 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 $D = [U(x = \infty) - U_{\mathrm{atequilibrium}}]$ , $D$ 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 Q140 Errorless 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.
$9 \times 10^{16} J$
CBSE PMT 2010 Q141 Errorless 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
Kerala PET 2010 Q142 Errorless POWER MCQ
A force $(4\hat{i} + \hat{j} - 2\hat{k})N$ acting on a body maintains its velocity at $(2\hat{i} + 2\hat{j} + 3\hat{k})ms^{-1}$ . The power exerted is
A.
4 W
B.
5 W
C.
2 W
D.
8 W
E.
1 W
AMU (Med.) 2010 Q143 Errorless Elastic and Inelastic Collision MCQ
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 $35^{\circ}$ 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 ball is
A.
$35^{\circ}$
B.
$50^{\circ}$
C.
$55^{\circ}$
D.
$60^{\circ}$
J & K CET 2010 Q144 Errorless 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.
$7.5 \, m \, s^{-1}$
Odisha JEE 2010 Q145 Errorless 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
CBSE PMT 2010 Q146 Errorless 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
Kerala PMT 2010 Q147 Errorless 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 Q148 Errorless 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
AIIMS 2010 Q149 Errorless Assertion and Reason MCQ
Assertion : The change in kinetic energy of a particle is equal to the work done on it by the net force. Reason : Change in kinetic energy of particle is equal to the work done only in case of a system of one particle.
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 Q150 Errorless 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