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Look at the activities listed below. Reason out whether or not... - Science
Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
• Suma is swimming in a pond.
• A donkey is carrying a load on its back.
• A wind-mill is lifting water from a well.
• A green plant is carrying out photosynthesis.
• An engine is pulling a train.
• Food grains are getting dried in the sun.
• A sailboat is moving due to wind energy.
• Suma is swimming in a pond:
Work is done. She applies a force to push the water backward and gets displaced in the forward direction.
• A donkey is carrying a load on its back:
Work is not done. The force exerted by the donkey (upward) acts perpendicular (90^\circ) to the direction of displacement (horizontal).
• A wind-mill is lifting water from a well:
Work is done. The windmill exerts a force to lift the water through a vertical distance (displacement).
• A green plant is carrying out photosynthesis:
Work is not done. There is no displacement of leaves or the plant during this process.
• An engine is pulling a train:
Work is done. The engine exerts a pulling force in the direction of the train's displacement.
• Food grains are getting dried in the sun:
Work is not done. The grains remain stationary; there is no displacement.
• A sailboat is moving due to wind energy:
Work is done. The wind exerts a force on the sail, causing the boat to be displaced.
