Work and energy are fundamental concepts in physics that describe the transfer and transformation of mechanical quantities.
How do Work and Energy interact in vital life processes and Machine operations?
Requirement of Life: Necessities for vital processes and Strenuous activities: All living beings require energy for their life processes and activities.
Activities that are more strenuous necessitate more energy.
Necessity for Life: Fueling vital activities for Survival and Mobility: Similarly, animals also need energy for various activities such as running, jumping, or moving away from threats.
Machines, on the other hand, often require fuel like petrol and diesel to operate.
Work in Physics: From everyday perceptions to Scientific principles:
Work: Everyday vs Scientific Definitions: Common parlance treats any physical or mental labor as work.
However, by the scientific definition, many activities we consider as “working hard” may involve little to no “work”.
Example: Pushing a rock without it moving or holding a load without moving it does not qualify as work in science, even if they tire you out.
Climbing stairs or a tree involves work because there is displacement against a force.
Scientific Principles and Conditions:
Pushing a pebble, pulling a trolley, and lifting a book are all examples where work is done in the scientific sense.
Two conditions must be met for work to be recognized in science:
A force should act on an object.
The object must undergo displacement.
If either condition is unmet, work hasn’t been done.
Work Done by a Constant Force: Positive and Negative Forces in Physics:
Definition: In the realm of work and energy, the definition states that work is the product of force and the displacement in the direction of the force: W = F × s.
Work has only magnitude, not direction.
The unit of work is the newton-meter (N m) or joule (J).
When force or displacement is zero, the work done is also zero.
Positive Work: Work done is positive when force and displacement are in the same direction.
Negative Work: Conversely, work is negative when the force acts opposite to the direction of displacement.
Force and Work: Dynamic Interplay in Positive and Negative Directions
Force and Displacement in the Same Direction:
Example: A baby pulls a toy car parallel to the ground.
The force exerted by the baby is in the direction of the car’s displacement. Here, the work done is calculated as the product of force and displacement.
In such cases, the work done is taken as positive.
Force Opposite to the Direction of Displacement:
Consider an object moving uniformly in one direction.
A retarding force, denoted as F, acts opposite to its movement.
The angle between the directions of the force and displacement is 180°.
If the object stops after displacement ‘s’, the work done by force F is negative.
It’s represented mathematically as either F × (–s) or (–F × s).
Comprehensive coverage with a concise format Integration of PYQ within the booklet Designed as per recent trends of Prelims questions हिंदी में भी उपलब्ध
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Comprehensive coverage with a concise format Integration of PYQ within the booklet Designed as per recent trends of Prelims questions हिंदी में भी उपलब्ध
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