Question 6 :
A juggler throws continuously balls at the rate ofthree in each second each with a velocity of $10\ ms^{-1}$. If the mass of each ball is $0.05\ kg$ hispower is:
Question 11 :
If $v$, $P$ and $E$ denote the velocity, momentum and kinetic energy of the particle, then:<br/>
Question 13 :
A machine gun fires $240$ bullets $per\ minute$ with a certain velocity. If the mass of each bullet is $10 gm$ and the power of the gun is $7.2 kW$, the velocity with which each bullet is fired must be:
Question 14 :
An X-ray tube is run at 50 kV.. the current flowing in it is 20 mA. The power of the tube is:
Question 18 :
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 19 :
A house uses 7 tubelight of 50 W each for 5 hours a day. The electrical energy consumption for one day is:
Question 20 :
Six electric appliances of 100 watts each are used for 6 hours. The electrical energy consumed is:
Question 21 :
A girl of mass $40\  kg$ climbs $20$ steps of a staircase, each measuring $20 \ cm$ high in $30\ s$.Calculate the power developed  by the girl.           [Take g = 10 $m/s^2$]
Question 25 :
If $120J$ of work is done in $2$ minutes by a water pump, the power of the pump is:
Question 26 :
If the values of force and length are increased four times then the unit of energy will increases by?
Question 27 :
If the gravitational field intensity at a point is given by $\displaystyle g=\frac{GM}{r^{2.5}}$Then the potential at distance $r$ is
Question 28 :
A body attains a height equal to the radius of theearth when projected from earth' surface. Thevelocity of the body with which it was projected is.
Question 29 :
The gravitational field due to a mass distribution is E=$\dfrac {K} {x^3}$ the x-direction. (K is a constant). Taking the gravitational potential to be zero at infinity, its value at the a distance x is:
Question 30 :
$\text{A diametrical tunnel is dug across the earth. A ball is dropped into the tunnel from one side.}$<br>$\text{ The velocity of the ball when it reaches the centre of the earth is}$<br>$[\text{Given: gravitational potential at the centre of earth} = -\dfrac{ 3 }{2} \left( \dfrac{ GM }{ R } \right)$