Podcast
Questions and Answers
Which activity would be considered as doing 'scientific work'?
Which activity would be considered as doing 'scientific work'?
- Pushing a rock that does not move
- Standing still with a heavy load on your head
- Climbing up the stairs and reaching the next floor (correct)
- Running in place
All strenuous activities require energy and are considered work according to scientific definitions.
All strenuous activities require energy and are considered work according to scientific definitions.
False (B)
What is the primary source of energy for living organisms?
What is the primary source of energy for living organisms?
food
Animals perform various activities such as jumping and running to find _____ or avoid dangers.
Animals perform various activities such as jumping and running to find _____ or avoid dangers.
Match the following terms with their definitions:
Match the following terms with their definitions:
What is one reason some engines require fuel like petrol and diesel?
What is one reason some engines require fuel like petrol and diesel?
Activities like playing in a field or watching a movie are always considered work.
Activities like playing in a field or watching a movie are always considered work.
According to scientific conception, what must happen for work to be done on an object?
According to scientific conception, what must happen for work to be done on an object?
In day-to-day life, we define work as any useful physical or mental labor, whereas in science, work is defined as __________.
In day-to-day life, we define work as any useful physical or mental labor, whereas in science, work is defined as __________.
Match the following scenarios with the corresponding concept of work:
Match the following scenarios with the corresponding concept of work:
Flashcards
Work (physics)
Work (physics)
Work, in physics, is done when a force causes an object to move a certain distance. Crucially, the object must move in the direction of the force.
Displacement
Displacement
Displacement is the change in position of an object. In physics, work is only done when an object moves a distance in the direction of the force.
Energy for life processes
Energy for life processes
Living things need energy to carry out basic life functions (like breathing, growing).
Energy for activities
Energy for activities
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No work done
No work done
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Work (everyday)
Work (everyday)
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Force acting, no movement
Force acting, no movement
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Movement without force
Movement without force
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Scientific view of work
Scientific view of work
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Study Notes
Work and Energy
- Work is different in everyday language and science.
- In science, work is done when a force causes an object to move in the direction of the force.
- Work is calculated as force multiplied by displacement (W = Fs).
- The unit of work is the joule (J) or Newton-meter (Nâ‹…m).
- If force and displacement are not in the same direction, work is calculated as W = Fs cos θ, where θ is the angle between them.
- Positive work is done when force and displacement are in the same direction; negative work is done when the force is opposite to the displacement.
- No work is done if there is no displacement.
Energy
- Energy is the capacity to do work.
- Energy has the same unit as work, the joule (J).
- Various forms of energy exist: mechanical, heat, chemical, electrical and light.
- Energy can be converted from one form to another, but it is never created or destroyed (law of conservation of energy).
Kinetic Energy
- Kinetic energy is the energy of motion.
- Kinetic energy is calculated as 1/2 * m * v^2, where m is mass and v is velocity.
Potential Energy
- Potential energy is the energy an object has due to its position or configuration.
- Gravitational potential energy is the energy an object has due to its height.
- It's calculated by mgh, where m is mass, g is acceleration due to gravity and h is height.
Power
- Power is the rate at which work is done or energy is transferred.
- It is calculated as work/time or energy/time.
- The unit of power is the watt (W), equal to 1 joule per second (J/s).
- Kilowatt-hour (kWh) is a larger unit of energy. 1kWh = 3.6 x 106 J.
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