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Work Power and Energy

267 Questions Start Errorless Test
All Exams Allen Objective Errorless
AIEEE 2002, 03 Q201 Errorless 2. Work Done by Variable Force MCQ
A spring of spring constant $5 \times 10^{3}$ N/m is stretched initially by 5cm from the unstretched position. Then the work required to stretch it further by another 5cm is
A.
6.25 N-m
B.
12.50 N-m
C.
18.75 N-m
D.
25.00 N-m
MP PMT 2002; CBSE PMT 2003, 06; UPSEAT 2004; Odisha PMT 2004; WB-JEE 2012 Q202 Errorless 2. Work Done by Variable Force MCQ
If a long spring is stretched by 0.02 m, its potential energy is U. If the spring is stretched by 0.1 m, then its potential energy will be
A.
$\frac{U}{5}$
B.
U
C.
5U
D.
25U
MP PET 2002 Q203 Errorless 3. Conservation of Energy and Momentum MCQ
In an explosion a body breaks up into two pieces of unequal masses. In this
A.
Both parts will have numerically equal momentum
B.
Lighter part will have more momentum
C.
Heavier part will have more momentum
D.
Both parts will have equal kinetic energy
RPET 2002 Q204 Errorless 3. Conservation of Energy and Momentum MCQ
A particle of mass m moving with velocity $V_{0}$ strikes a simple pendulum of mass m and sticks to it. The maximum height attained by the pendulum will be
A.
$h = \frac{V_{0}^{2}}{8g}$
B.
$\sqrt{V_{0}g}$
C.
$2\sqrt{\frac{V_{0}}{g}}$
D.
$\frac{V_{0}^{2}}{4g}$
Kerala PET 2002 Q205 Errorless 3. Conservation of Energy and Momentum MCQ
A particle of mass m at rest is acted upon by a force F for a time t. Its kinetic energy after an interval t is
A.
$\frac{F^{2}t^{2}}{m}$
B.
$\frac{F^{2}t^{2}}{2m}$
C.
$\frac{F^{2}t^{2}}{3m}$
D.
$\frac{Ft}{2m}$
BHU 2002 Q206 Errorless 3. Conservation of Energy and Momentum MCQ
Two bodies moving towards each other collide and move away in opposite directions. There is some rise in temperature of bodies because a part of the kinetic energy is converted into
A.
Heat energy
B.
Electrical energy
C.
Nuclear energy
D.
Mechanical energy
Pb. PET 2002 Q207 Errorless 3. Conservation of Energy and Momentum MCQ
If a man increase his speed by 2 m/s, his K.E. is doubled, the original speed of the man is
A.
$(1 + 2\sqrt{2})$ m/s
B.
4 m/s
C.
$(2 + 2\sqrt{2})$ m/s
D.
$(2 + \sqrt{2})$ m/s
Kerala PMT 2002 Q208 Errorless 3. Conservation of Energy and Momentum MCQ
A machine which is 75 percent efficient, uses 12 joules of energy in lifting up a $1\mathrm{kg}$ mass through a certain distance. The mass is then allowed to fall through that distance. The velocity at the end of its fall is (in $ms^{-1}$ )
A.
$\sqrt{24}$
B.
$\sqrt{32}$
C.
$\sqrt{18}$
D.
$\sqrt{9}$
AIEEE 2002; DCE 2002; BCECE 2006; WB-JEE 2012 Q209 Errorless 3. Conservation of Energy and Momentum MCQ
If a body looses half of its velocity on penetrating 3 cm in a wooden block, then how much will it penetrate more before coming to rest
A.
1 cm
B.
2 cm
C.
3 cm
D.
4 cm
Pb. PMT 2002; J & K CET 2004 Q210 Errorless 3. Conservation of Energy and Momentum MCQ
A body moving with velocity v has momentum and kinetic energy numerically equal. What is the value of v
A.
2m/s
B.
$\sqrt{2}$ m/s
C.
1m/s
D.
0.2 m/s
JIPMER 2002 Q211 Errorless 4. Power MCQ
A pump motor is used to deliver water at a certain rate from a given pipe. To obtain twice as much water from the same pipe in the same time, power of the motor has to be increased to
A.
16 times
B.
4 times
C.
8 times
D.
2 times
Kerala PET 2002 Q212 Errorless 4. Power MCQ
A quarter horse power motor runs at a speed of 600 r.p.m. Assuming 40% efficiency the work done by the motor in one rotation will be
A.
7.46 J
B.
7400 J
C.
7.46 ergs
D.
74.6 J
Kerala PET 2002; CBSE PMT (Mains) 2010 Q213 Errorless 4. Power MCQ
A particle of mass M starting from rest undergoes uniform acceleration. If the speed acquired in time T is V, the power delivered to the particle is
A.
$\frac{MV^{2}}{T}$
B.
$\frac{1}{2}\frac{MV^{2}}{T^{2}}$
C.
$\frac{MV^{2}}{T^{2}}$
D.
$\frac{1}{2}\frac{MV^{2}}{T}$
Kerala PET 2002; EAMCET 2009 Q214 Errorless 5. Elastic and Inelastic Collision MCQ
A body of mass 2kg makes an elastic collision with another body at rest and continues to move in the original direction with one fourth of its original speed. The mass of the second body which collides with the first body is
A.
2 kg
B.
1.2 kg
C.
3 kg
D.
1.5 kg
AFMC 2002; RPMT 2003 Q215 Errorless 5. Elastic and Inelastic Collision MCQ
Two masses $m_A$ and $m_B$ moving with velocities $v_A$ and $v_B$ in opposite directions collide elastically. After that the masses $m_A$ and $m_B$ move with velocity $v_B$ and $v_A$ respectively. The ratio $(m_A / m_B)$ is
A.
1
B.
$\frac{v_A - v_B}{v_A + v_B}$
C.
$(m_A + m_B) / m_A$
D.
$v_A / v_B$
Kerala PMT 2002; MP PET 2002; WB-JEE 2013 Q216 Errorless 6. Perfectly Inelastic Collision MCQ
A bullet of mass m moving with velocity v strikes a block of mass M at rest and gets embedded into it. The kinetic energy of the composite block will be
A.
$\frac{1}{2}mv^{2}\times\frac{m}{(m+M)}$
B.
$\frac{1}{2}mv^{2}\times\frac{M}{(m+M)}$
C.
$\frac{1}{2}mv^{2}\times\frac{(M+m)}{M}$
D.
$\frac{1}{2}Mv^{2}\times\frac{m}{(m+M)}$
IIT-JEE (Screening) 2002; DCE 2006 Q217 Errorless 8. Graphical Questions MCQ
A particle which is constrained to move along the $x$ -axis, is subjected to a force in the same direction which varies with the distance $x$ of the particle from the origin as $F(x) = -kx + ax^3$ . Here $k$ and $a$ are positive constants. For $x \geq 0$ , the functional from of the potential energy $U(x)$ of the particle is
A.
B.
C.
D.
MP PMT 2001; CBSE PMT 2004 Q218 Errorless 2. Work Done by Variable Force MCQ
A body of mass 0.1 kg moving with a velocity of 10 m/s hits a spring (fixed at the other end) of force constant 1000 N/m and comes to rest after compressing the spring. The compression of the spring is
A.
0.01m
B.
0.1m
C.
0.2m
D.
0.5m
BCECE 2001; CBSE PMT 2007; AIIMS 2008; ! Q219 Errorless 3. Conservation of Energy and Momentum MCQ
A vertical spring with force constant $K$ is fixed on a table. A ball of mass $m$ at a height $h$ above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance $d$ . The net work done in the process is (images/be8937a3a0433e0f15a44a7540122b8cc89d7a194dca520d0cde82c3001f4c94.jpg)
A.
$mg(h+d)+\frac{1}{2}Kd^{2}$
B.
$mg(h+d)-\frac{1}{2}Kd^{2}$
C.
$mg(h-d)-\frac{1}{2}Kd^{2}$
D.
$mg(h-d)+\frac{1}{2}Kd^{2}$
Kerala (Engg.) 2001; EAMCET 2001; DPMT 2004; UP CPMT 2006 Q220 Errorless 4. Power MCQ
A truck of mass 30,000kg moves up an inclined plane of slope 1 in 100 at a speed of 30 kmph. The power of the truck is (Given $g = 10ms^{-2}$ )
A.
25 kW
B.
10 kW
C.
5 kW
D.
2.5 kW
DCE 2001, 02; Odisha JEE 2002 Q221 Errorless 5. Elastic and Inelastic Collision MCQ
A body of mass $M_{1}$ collides elastically with another mass $M_{2}$ at rest. There is maximum transfer of energy when
A.
$M_{1} > M_{2}$
B.
$M_{1} < M_{2}$
C.
$M_{1} = M_{2}$
D.
Same for all values of $M_{1}$ and $M_{2}$
UPSEAT 2001; EAMCET 2009 Q222 Errorless 5. Elastic and Inelastic Collision MCQ
A body at rest breaks up into 3 parts. If 2 parts having equal masses fly off perpendicularly each after with a velocity of $12m/s$ , then the velocity of the third part which has 3 times mass of each part is
A.
$4\sqrt{2} m/s$ at an angle of $45^{\circ}$ from each body
B.
$24\sqrt{2} m/s$ at an angle of $135^{\circ}$ from each body
C.
$6\sqrt{2} m/s$ at $135^{\circ}$ from each body
D.
$4\sqrt{2} m/s$ at $135^{\circ}$ from each body
UPSEAT 2000; CPMT 2002; Pb. PET 2004; MP PMT 2012 Q223 Errorless 2. Work Done by Variable Force MCQ
The potential energy of a certain spring when stretched through a distance ā€˜Sā€™ is 10 joule. The amount of work (in joule) that must be done on this spring to stretch it through an additional distance ā€˜Sā€™ will be
A.
30
B.
40
C.
10
D.
20
MHCET 2000; Kerala PMT 2008; AMU PMT 2009; AIPMT (Cancelled) 2015 Q224 Errorless 2. Work Done by Variable Force MCQ
Two similar springs P and Q have spring constants $K_{P}$ and $K_{Q}$ , such that $K_{P} > K_{Q}$ . They are stretched, first by the same amount (case a), then by the same force (case b). The work done by the springs $W_{P}$ and $W_{Q}$ are related as, in case (a) and case (b), respectively
A.
$W_{P} = W_{Q}; W_{P} = W_{Q}$
B.
$W_{P} > W_{Q}; W_{Q} > W_{P}$
C.
$W_{P} < W_{Q}; W_{Q} < W_{P}$
D.
$W_{P} = W_{Q}; W_{P} > W_{Q}$
DPMT 2000; Odisha JEE 2005 Q225 Errorless 5. Elastic and Inelastic Collision MCQ
A mass of 100g strikes the wall with speed 5m/s at an angle as shown in figure and it rebounds with the same speed. If the contact time is $2 \times 10^{-3}$ sec, what is the force applied on the mass by the wall
A.
$250\sqrt{3}$ N to right
B.
250 N to right
C.
$250\sqrt{3}$ N to left
D.
250 N to left