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Work Power and Energy

267 Questions Start Errorless Test
All Exams Allen Objective Errorless
Kerala PET 2005 Q151 Errorless 1. Work Done by Constant Force MCQ
A ball is released from the top of a tower. The ratio of work done by force of gravity in first, second and third second of the motion of the ball is
A.
1:2:3
B.
1:4:9
C.
1:3:5
D.
1:5:3
Kerala PMT 2005 Q152 Errorless 2. Work Done by Variable Force MCQ
Which one of the following is not a conservative force
A.
Gravitational force
B.
Electrostatic force between two charges
C.
Magnetic force between two magnetic dipoles
D.
Frictional force
AIEEE 2005 Q153 Errorless 3. Conservation of Energy and Momentum MCQ
The block of mass $M$ moving on the frictionless horizontal surface collides with the spring of spring constant $K$ and compresses it by length $L$ . The maximum momentum of the block after collision is
A.
Zero
B.
$\frac{ML^2}{K}$
C.
$\sqrt{MK} L$
D.
$\frac{KL^2}{2M}$
AIEEE 2005; AIIMS 2007 Q154 Errorless 3. Conservation of Energy and Momentum MCQ
A spherical ball of mass 20 kg is stationary at the top of a hill of height 100 m. It slides down a smooth surface to the ground, then climbs up another hill of height 30 m and finally slides down to a horizontal base at a height of 20 m above the ground. The velocity attained by the ball is
A.
10 m/s
B.
$10\sqrt{30}$ m/s
C.
40 m/s
D.
20 m/s
RPMT 2005 Q155 Errorless 4. Power MCQ
An electric immersion heater of 1.08 kW is immersed in water. After the water has reached a temperature of $100^{\circ}$ C, how much time will be required to produce 100g of steam
A.
210 s
B.
105 s
C.
420 s
D.
50 s
RPMT 2005 Q156 Errorless 4. Power MCQ
An apple gives 21 kJ energy to a boy. How much height he can climb by using this energy if his efficiency is 28% (mass of boy = 40 kg)
A.
22.5 m
B.
15 m
C.
10 m
D.
5 m
J & K CET 2005 Q157 Errorless 4. Power MCQ
If the heart pushes 1 cc of blood in one second under pressure $20000N / m^2$ the power of heart is
A.
$0.02W$
B.
$400W$
C.
$5\times 10^{-10}W$
D.
$0.2W$
J & K CET 2005; NEET (Karnataka) 2013 Q158 Errorless 4. Power MCQ
A man does a given amount of work in 10 sec. Another man does the same amount of work in 20 sec. The ratio of the output power of first man to the second man is
A.
1
B.
1/2
C.
2/1
D.
None of these
AIEEE 2005; AIPMT 2015 Q159 Errorless 5. Elastic and Inelastic Collision MCQ
On a frictionless surface a block of mass M moving at speed v collides elastically with another block of same mass M which is initially at rest. After collision the first block moves at an angle $\theta$ to its initial direction and has a speed $\frac{v}{3}$ . The second block's speed after the collision is
A.
$\frac{3}{4}v$
B.
$\frac{3}{\sqrt{2}}v$
C.
$\frac{\sqrt{3}}{2}v$
D.
$\frac{2\sqrt{2}}{3}v$
KCET 2005; Kerala PET 2009 Q160 Errorless 8. Graphical Questions MCQ
The relationship between the force F and position x of a body is as shown in figure. The work done in displacing the body from x = 1 m to x = 5 m will be
A.
$30J$
B.
15 J
C.
25 J
D.
20 J
CBSE PMT 2005 Q161 Errorless 8. Graphical Questions MCQ
A force $F$ acting on an object varies with distance $x$ as shown here. The force is in newton and $x$ in metre. The work done by the force in moving the object from $x = 0$ to $x = 6m$ is
A.
4.5 J
B.
13.5 J
C.
9.0 J
D.
$18.0J$
AIEEE 2004 Q162 Errorless 1. Work Done by Constant Force MCQ
A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, the motion of the particle takes place in a plane. It follows that
A.
Its velocity is constant
B.
Its acceleration is constant
C.
Its kinetic energy is constant
D.
It moves in a straight line
DCE 2004 Q163 Errorless 1. Work Done by Constant Force MCQ
A man starts walking from a point on the surface of earth (assumed smooth) and reaches diagonally opposite point. What is the work done by him
A.
Zero
B.
Positive
C.
Negative
D.
Nothing can be said
BCECE 2004 Q164 Errorless 1. Work Done by Constant Force MCQ
A ball of mass m moves with speed v and strikes a wall having infinite mass and it returns with same speed then the work done by the ball on the wall is
A.
Zero
B.
mv J
C.
m/v.J
D.
v/m J
AIEEE 2004 Q165 Errorless 2. Work Done by Variable Force MCQ
A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement x is proportional to
A.
$x^{2}$
B.
$e^{x}$
C.
x
D.
$\log_{e}x$
DCE 2004 Q166 Errorless 2. Work Done by Variable Force MCQ
Natural length of a spring is 60 cm, and its spring constant is 4000 N/m. A mass of 20 kg is hung from it. The extension produced in the spring is, (Take $g = 9.8 \, m/s^{2}$ )
A.
4.9 cm
B.
0.49 cm
C.
9.4 cm
D.
0.94 cm
AFMC 2004; Odisha JEE 2008 Q167 Errorless 3. Conservation of Energy and Momentum MCQ
A rifle bullet loses $1/20^{th}$ of its velocity in passing through a plank. The least number of such planks required just to stop the bullet is
A.
5
B.
10
C.
11
D.
20
Pb. PET 2004 Q168 Errorless 3. Conservation of Energy and Momentum MCQ
If a shell fired from a cannon, explodes in mid air, then
A.
Its total kinetic energy increases
B.
Its total momentum increases
C.
Its total momentum decreases
D.
None of these
DCE 2004 Q169 Errorless 3. Conservation of Energy and Momentum MCQ
A body is moving with a velocity v, breaks up into two equal parts. One of the part retraces back with velocity v. Then the velocity of the other part is
A.
v in forward direction
B.
3v in forward direction
C.
v in backward direction
D.
3v in backward direction
CBSE PMT 2004 Q170 Errorless 3. Conservation of Energy and Momentum MCQ
A ball of mass 2kg and another of mass 4kg are dropped together from a 60 feet tall building. After a fall of 30 feet each towards earth, their respective kinetic energies will be in the ratio of
A.
$\sqrt{2}:1$
B.
1:4
C.
1:2
D.
$1:\sqrt{2}$
KCET 2004 Q171 Errorless 3. Conservation of Energy and Momentum MCQ
A bullet moving with a speed of $100 \, ms^{-1}$ can just penetrate two planks of equal thickness. Then the number of such planks penetrated by the same bullet when the speed is doubled will be
A.
4
B.
8
C.
6
D.
10
AIIMS 2004 Q172 Errorless 3. Conservation of Energy and Momentum MCQ
A bomb of mass 3.0 kg explodes in air into two pieces of masses 2.0 kg and 1.0 kg. The smaller mass goes at a speed of 80 m/s. The total energy imparted to the two fragments is
A.
1.07 kJ
B.
2.14 kJ
C.
2.4 kJ
D.
4.8 kJ
DCE 2004 Q173 Errorless 3. Conservation of Energy and Momentum MCQ
A bomb is kept stationary at a point. It suddenly explodes into two fragments of masses 1 g and 3 g. The total K.E. of the fragments is $6.4 \times 10^{4} J$ . What is the K.E. of the smaller fragment
A.
$2.5 \times 10^{4} J$
B.
$3.5 \times 10^{4} J$
C.
$4.8 \times 10^{4} J$
D.
$5.2 \times 10^{4} J$
UPSEAT 2004 Q174 Errorless 3. Conservation of Energy and Momentum MCQ
An object of mass 3m splits into three equal fragments. Two fragments have velocities $v\hat{j}$ and $v\hat{i}$ . The velocity of the third fragment is
A.
$v(\hat{j}-\hat{i})$
B.
$v(\hat{i}-\hat{j})$
C.
$-v(\hat{i}+\hat{j})$
D.
$\frac{v(\hat{i}+\hat{j})}{\sqrt{2}}$
Odisha PMT 2004 Q175 Errorless 3. Conservation of Energy and Momentum MCQ
Four particles given, have same momentum. Which has maximum kinetic energy
A.
Proton
B.
Electron
C.
Deutron
D.
$\alpha$ -particles