Question 2 :
The power of a motor pump is $2\  kW$. How much water per minute the pump can raise to a height of 10 m? $(Given \:g = 10 \: m \: s^{-2})$<br/>
Question 6 :
A lamp consumes 1000 J of electrical energy in 10 s. What is its power ?<br><br>
Question 7 :
An object is thrown vertically upwards. As it rise, its total energy
Question 9 :
Assertion: Total energy is conserved in moving a satellite to higher orbit.
Reason: Sum of change in PE and KE is same in magnitude and opposite in nature
Question 11 :
A car of mass $2,000 kg$ is lifted up a distance of $30 m$ by a crane in $1\ minute$. A second crane does the same job in $2\ minutes$.The power supplied by first crane is:
Question 12 :
If the spinning speed of the earth is increased, thenthe weight of the body at the equator.
Question 13 :
Which of the following must be known in order to determine the power output of an automobile? <br>
Question 14 :
An electric heater of power $3 \ kW$ is used for $10 \ h$. How much energy does it consume? Express you answer in $kWh$.
Question 16 :
If the power of the motor of a water pump is $3\ kW$, then the volume of water that can be liftedto a height of $10\ m$ in one minute by the pump is ($g= 10 \ m /s^{2}$) :
Question 17 :
The velocity acquired by a charged particle of mass $m$ and charge $Q$ accelerated from rest by a potential of $V$ is
Question 20 :
When the time taken to complete a given amount of work increases, then,
Question 22 :
If force $\vec{F} = (15\hat{i} + 60 \hat{j} - 3\hat{k}) N$ and velocity $\vec{v} = (-4\hat{i} + 2\hat{j} + 5\hat{k})$ m/s, then instantaneous power is
Question 23 :
Compute the power at which a butterfly of mass 1.0 g will move upward  at a rate of 0.5 $ms^{-1}$ against the force of gravity? (given $g = 10 \ ms^{-2}$)
Question 24 :
A house uses 7 tubelight of 50 W each for 5 hours a day. The electrical energy consumption for one day is:
Question 25 :
How much energy does a 60W electric bulbtransfer in 1 minute?
Question 26 :
An electric heater is rated 1500 W. How much energy does it use in 10 hours ? <br><br>
Question 27 :
If $E$ represents total mechanical energy of a system while $U$ represents the potential energy, then $E-U$ is:
Question 28 :
What does the slope of work-time curve at any instant represent?
Question 29 :
If $v$, $P$ and $E$ denote the velocity, momentum and kinetic energy of the particle, then:<br/>
Question 32 :
Coolie A takes $1$min to raise a box of mass m through a height of $2.0$m. another coolie B takes $30$s for the same job. Which one has greater power?
Question 33 :
Mohan uses one television of $100$ W for $10$ hrs how much energy is consumed by Mohan.
Question 34 :
A machine gun fires $420$ bullets $per\ minute$. The velocity of each of the bullets is $300 m s^{-1}$ and the mass of each bullet is $1 gm$. The power of machine gun is:
Question 35 :
When a work of 1 joule is done in 1 s, the power is:<br/><br/>
Question 37 :
The power of a crane is 6.25 kW. How much mass of coal it can lift in 1 hour from a mine of 100 m depth? The efficiency of the crane is 80% and $g = 10 \ m s^{-2}$.
Question 39 :
A car of mass $2,000 kg$ is lifted up a distance of $30 m$ by a crane in $1\ minute$. A second crane does the same job in $2\ minutes$. The power supplied by second crane is:
Question 41 :
Which one of he following does not contribute to conservation of energy resources?
Question 43 :
An engine lifts a load of $1200\ N$ from a depth of $200 \ m$ in 4  minutes bringing it to the ground level. The power developed by the engine is:
Question 46 :
When time taken to complete a given amount of work increases, then:
Question 47 :
A planet whose mass and radius are both half of that of earth. Acceleration due to gravity(g) at its surface should be:
Question 48 :
At which depth, we get the necessary temperature for OTEC in the ocean?
Question 49 :
The ratio of the total work done or total energy consumed to the total time taken is called:<br/>
Question 50 :
The power of a pump takes 10 s to lift 100 kg of water tank situated at a height of 20 m is:
