हिंदी

Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’. A sailboat is moving due to wind energy. - Science

Advertisements
Advertisements

प्रश्न

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

A sailboat is moving due to wind energy.

लघु उत्तरीय

उत्तर

  • Wind energy applies a force on the sailboat to push it in the forward direction.
  • Therefore, there is a displacement in the boat in the direction of force.
  • Hence, work is done by wind on the boat.
shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 11: Work and Energy - Exercises [पृष्ठ १५८]

APPEARS IN

एनसीईआरटी Science [English] Class 9
अध्याय 11 Work and Energy
Exercises | Q 1. 7 | पृष्ठ १५८

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?


Explain briefly why the work done by a fielder when he takes a catch in a cricket match is negative.


A force acts on a body and displaces it by a distance S in a direction at an angle θ with the direction of the force. What should be the value of θ to get the maximum positive work?


In which of the following cases, is work being done?
(i) A man pushing a wall.
(ii) a coolie standing with a load of 12 kgf on his head.
(iii) A boy climbing up a staircase.


Name the forms of energy which a wound-up watch spring possesses.


The power of a motor is 40 kW. At what speed can the motor raise a load of 20,000 N?


In case of negative work, the angle between the force and displacement is :


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.


Explain the difference between a uniform linear motion and a uniform circular motion.


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

What is the amount of energy spent by the heart in pumping blood through the body?

Name the type of energy possessed by a
(i) stretched catapult        (ii) hot iron
(iii) wound up clock


Name the physical quantity whose SI unit is Nm.

A body is pivoted at a point. A force of 10 N is applied at a distance of 30 cm from the pivot. Find the moment of force about the pivot.

A boy pulls a box up to 10 m with a force of 5 kgf. Calculate the work done by him.


A bullet is of mass 'm' g and is moving with a velocity 'v' m/s. Find the kinetic energy of the bullet when
(a) The mass is doubled,
(b) The velocity is tripled.


How much energy is gained by a box of mass 20 kg when a man, runs carrying the box with a speed of 3 m/s-1 to catch the bus?


Define force. Is force a scalar or a vector quantity?


A coolie is pushing a box weighing 1500 N up an inclined plane 7.5 m long on to a platform, 2.5 m above the ground.
(i) Calculate the mechanical advantage of the inclined plane. (ii) Calculate the effort applied by the coolie.
(iii) In actual practice, the coolie needs to apply more effort than what is calculated. Give one reason why you think the coolie needs to apply more effort.


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

A donkey is carrying a load on its back.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×