Advertisements
Advertisements
Question
An electric motor of power 100 W is used to drive the stirrer in a water bath. If 50% of the energy supplied to the motor is spent in stirring the water. Calculate the work done on the water in one minute.
Advertisements
Solution
An Electric motor :
Power (P) = 100 watt.
Time (t) = 1 minute = 60 seconds
∴ Work done by motor = Produced energy
= P × t
= 100 × 60
= 6000 Joule
∴ Work done on water by motor = 50% of total produced energy
`=50/100xx6000`
= 3000 Joule.
RELATED QUESTIONS
Write the expression for work done by a force.
What are the two kinds of mechanical energy?
A bullet of mass 0.5 kg slows down from a speed of 5 m s-1 to that of 3 m s-1. Calculate the change in kinetic energy of the ball.
Fill in the blank with suitable word :
1 joule is the work done when a force of 1 __________ moves an object through a distance of one __________ in the direction of __________.
Ravi applied a force of 10 N and moved a book 30 cm in the direction of the force. How much was the work done by Ravi?
Name the physical quantity whose SI unit is Nm.
Is work done a scalar or a vector physical quantity?
If an electric bulb of 100 watt is lighted for 2 hours, how much electric energy would be consumed?
Give an example
Electrical energy changes to heat energy.
A uniform chain of length 2 m is kept on a table such that a length of 60 cm hangs freely from the edge of the table. The total mass of the chain is 4 kg. What is the work done in pulling the entire chain on the table?
