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Work, Power & Energy

769 Questions Start Allen Test
All Exams Allen Advance Errorless
Kerala PMT 2010 Q226 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 Q227 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
IIT-JEE 2010 Q228 Errorless 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 Q229 Errorless 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.
2010 Q230 Advance ARCHIVE: JEE MAIN 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 constant and x is the distance between the atoms. If the dissociation energy of the molecule is $D=\left[U(x=\infty)-U_{\text{atequilibrium}}\right]$ , D is
A.
$\frac{b^{2}}{6a}$
B.
$\frac{b^{2}}{2a}$
C.
$\frac{b^{2}}{12a}$
D.
$\frac{b^{2}}{4a}$
IIT-JEE 2010 Q231 Advance ARCHIVE: JEE ADVANCED MCQ
A block of mass $2\mathrm{kg}$ 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 $4.5\mathrm{s}$ is
A.
4.50 J
B.
7.50 J
C.
5.06 J
D.
14.06 J
CBSE PMT 2009 Q232 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
EAMCET 2009 Q233 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 Q234 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 Q235 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 image.png
A.
3 m/s
B.
4 m/s
C.
5 m/s
D.
1 m/s
Kerala PET 2009 Q236 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 = 16 m is
A.
$45\mathrm{J}$
B.
$30\mathrm{J}$
C.
70 J
D.
135 J
E.
20 J
KCET 2009 Q237 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 Q238 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
A.
5 J
B.
10 J
C.
15 J
D.
2.5 J
AIEEE 2009 Q239 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.

WB-JEE 2008 Q240 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 Q241 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.
$50 \mathrm{~ms}^{-1}$
B.
$9 \mathrm{~ms}^{-1}$
C.
$40 \mathrm{~ms}^{-1}$
D.
$60 \mathrm{~ms}^{-1}$
E.
$90 \mathrm{~ms}^{-1}$
Kerala PET 2008 Q242 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 Q243 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.
$2 \times 10^{5} J - 3 \times 10^{5} J$
B.
20,000 J - 50,000 J
C.
2,000 J - 5,000 J
D.
200 J - 500 J
CBSE PMT 2008 Q244 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 Q245 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.
$\frac{M}{4}(u_2 - u_1)^2$
IIT-JEE 2008 Q246 Errorless JEE Section MSQ
Two balls, having linear momenta $\vec{p}_1 = p\hat{i}$ and $\vec{p}_2 = -\vec{p}\hat{i}$ , undergo a collision in free space. There is no external force acting on the balls. Let $\vec{p}_1$ and $\vec{p}_2$ be their final momenta. The following option(s) is(are) NOT ALLOWED for any non-zero value of $p, a_1, a_2, b_1, b_2, c_1$ and $c_2$
A.
$\vec{p}_1 = a_1\hat{i} +b_1\hat{j} +c_1\hat{k},\vec{p}_2 = a_2\hat{i} +b_2\hat{j}$
B.
$\vec{p}_1 = c_1\hat{k}$ , $\vec{p}_2 = c_2\hat{k}$
C.
$\vec{p}_1 = a_1\hat{i} +b_1\hat{j} +c_1\hat{k},\vec{p}_2 = a_2\hat{i} +b_2\hat{j} -c_1\hat{k}$
D.
$\vec{p}_1 = a_1\hat{i} +b_1\hat{j},\vec{p}_2 = a_2\hat{i} +b_1\hat{j}$
IIT-JEE 2008 Q247 Errorless JEE Section MCQ
A small block of mass M moves on a frictionless surface of an inclined plane, as shown in figure. The angle of the incline suddenly changes from $60^{\circ}$ to $30^{\circ}$ at point B. The block is initially at rest at A. Assume that collisions between the block and the incline are totally inelastic ( $g = 10 \, m/s^{2}$ ). The speed of the block at point B immediately after it strikes the second incline is
A.
$\sqrt{60}$ m/s
B.
$\sqrt{45}$ m/s
C.
$\sqrt{30}$ m/s
D.
$\sqrt{15}$ m/s
IIT-JEE 2008 Q248 Errorless JEE Section MCQ
A small block of mass M moves on a frictionless surface of an inclined plane, as shown in figure. The angle of the incline suddenly changes from $60^{\circ}$ to $30^{\circ}$ at point B. The block is initially at rest at A. Assume that collisions between the block and the incline are totally inelastic ( $g = 10 \, m/s^{2}$ ). The speed of the block at point C, immediately before it leaves the second incline is
A.
$\sqrt{120} m / s$
B.
$\sqrt{105} m / s$
C.
$\sqrt{90} m / s$
D.
$\sqrt{75} m / s$
IIT-JEE 2008 Q249 Errorless JEE Section MCQ
A small block of mass M moves on a frictionless surface of an inclined plane, as shown in figure. The angle of the incline suddenly changes from $60^{\circ}$ to $30^{\circ}$ at point B. The block is initially at rest at A. Assume that collisions between the block and the incline are totally inelastic ( $g = 10 \, m/s^{2}$ ). If collision between the block and the incline is completely elastic, then the vertical (upward) component of the velocity of the block at point B, immediately after it strikes the second incline is
A.
$\sqrt{30}$ m/s
B.
$\sqrt{15}$ m/s
C.
0
D.
$-\sqrt{15}$ m/s
IIT-JEE 2008 Q250 Advance ARCHIVE: JEE ADVANCED MCQ
A block (B) is attached to two unstretched springs $S_{1}$ and $S_{2}$ with spring constants k and 4k, respectively. The other ends are attached to two supports $M_{1}$ and $M_{2}$ not attached to the walls. The springs and supports have negligible mass. There is no friction anywhere. The block B is displaced towards wall 1 by a small distance x and released. The block returns and moves a maximum distance y towards wall 2. Displacements x and y are measured with respect to the equilibrium position of the block B. The ratio $\frac{y}{x}$ is
A.
4
B.
2
C.
$\frac{1}{2}$
D.
$\frac{1}{4}$