English

Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’. A wind-mill is lifting water from a well. - Science

Advertisements
Advertisements

Question

Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.

A wind-mill is lifting water from a well.

Short Answer

Solution

  • A wind-mill works against the gravitational force to lift water.
  • Hence, work is done by the wind-mill in lifting water from the well.
shaalaa.com
  Is there an error in this question or solution?
Chapter 11: Work and Energy - Exercises [Page 158]

APPEARS IN

NCERT Science [English] Class 9
Chapter 11 Work and Energy
Exercises | Q 1. 3 | Page 158

Video TutorialsVIEW ALL [1]

RELATED QUESTIONS

The S.I. unit of work is


In which of the following cases is work being done:

  1. A boy pushing a heavy rock
  2. A boy climbing up the stairs
  3. A coolie standing with a box on his head
  4. A girl moving on the road.

Express joule in terms of erg.


State two advantage of producing hydroelectricity.


What should be the angle between the direction of force and the direction of motion of a body so that the work done is zero?


In which of the following case the work done by a force will be maximum : when the angle between the direction of force and direction of motion is 0° or 90°?


A max X goes to the top of a building by a vertical spiral staircase. Another man Y of the same mass goes to the top of the same building by a slanting ladder. Which of the two does more work against gravity and why?


Draw a neat labeled diagram to show the direction of two forces acting on a body to produce rotation in it. Also mark the point about which rotation takes place.


Can every force produce work?


It takes 20 s for A to climb up the stairs, while B does the same in 15 s. compare the (i) work done, and (ii) power developed by A and B.

Define kinetic energy.

A moving object of mass 30 kg has 60 J of kinetic energy. What is its speed?

A body is thrown vertically upwards. Its velocity keeps on changing. What happens to its K.E. when does its velocity become zero?

Is it easier to turn a steering wheel of large diameter than that of small diameter? Why?

A water pump raises 80 kg of water through a height of 20 m in 10 s. Calculate the power of the pump.

State the energy changes which take place when A piece of magnesium wire is burnt in a jar of oxygen.


A lead bullet moving at 70 ms-1 is brought to rest on hitting a target. If 80% of its energy is converted into heat energy, find the rise in temperature (Sp. Heat cap. Of lead is 140 J/kgK).

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.


A ______ should act on an object.


A body of mass 0.5 kg travels on straight line path with velocity v = (3x2 + 4) m/s. The net work done by the force during its displacement from x = 0 tox = 2 m is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×