Question 4 :
A house uses 7 tubelight of 50 W each for 5 hours a day. The electrical energy consumption for one day is:
Question 5 :
If a man of $30$ kilograms climbs stairs in $4$ seconds when height of stairs is $5$ meters, power output produced will be:<br/>
Question 6 :
How much energy does a 60W electric bulbtransfer in 1 minute?
Question 7 :
What does the slope of work-time curve at any instant represent?
Question 11 :
Power spent by a body depends on the time for which it does work.
Question 12 :
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 :<br/>
Question 13 :
A man weighing $60\ kg$ climbs up a staircase carrying a load of $20\ kg$ on his head. The stair case has $20$ steps each of height $0.2\ m$. If he takes $10\ s$ to climb, find his power.
Question 14 :
A man raises a box of mass $50kg$ to a height of $2m$ in $2$ minutes, while another man raises the same box to the same height in $5$ minutes. Ratio of the power developed by them:
Question 15 :
A constant force of $2.50\mathrm { N }$ accelerates a stationary particle of mass $15\mathrm { g }$ through a displacement of $2.5\mathrm { m }$The average power delivered is
Question 16 :
A body of mass $m$ is raised to a height $10R$ from the surface of the earth, where $R$ is the radius of the earth. The increase in potential energy is ($G =$ universal constant of gravitation, $M =$ mass of the earth and $g =$ acceleration due to gravity)
Question 17 :
From a waterfall, water is pouring down at the rate of 160 kg per second on the blades of a turbine. If the height of the fall be 50 m, the power delivered to the turbine is approximately equal to (Take $g=9.8 \ m/s^2$)<br/>
Question 18 :
A man weighing $70$ kg climb staircase with a speed of $10$ steps/min.If the height of each step is $20$ cm, the power consumed is
Question 19 :
In an hydroelectric power station, the height of dam is 10 m. How many kg of water must fall per second on the blades of a turbine in order to generate 1 MW of electric power?
Question 20 :
The work done by the heart is $1J$ per beat. Calculate the power of the heart if it beats $72$ times in a minute.
