Podcast
Questions and Answers
What does 'work' mean in science?
What does 'work' mean in science?
Work is the energy transferred to an object when a force moves it.
How are 'work done' and 'energy transferred' linked?
How are 'work done' and 'energy transferred' linked?
They are equal.
What are the units for work done?
What are the units for work done?
Convert 250cm into m.
Convert 250cm into m.
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Which is the correct equation for force? (Rearrange W=Fxs)
Which is the correct equation for force? (Rearrange W=Fxs)
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What is the equation for kinetic energy?
What is the equation for kinetic energy?
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What is the equation for elastic potential energy?
What is the equation for elastic potential energy?
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What is the equation for gravitational potential energy?
What is the equation for gravitational potential energy?
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What energy transfers occur when a person throws a ball up in the air, and it falls back down?
What energy transfers occur when a person throws a ball up in the air, and it falls back down?
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Whenever work is done to overcome friction, energy is transferred as what?
Whenever work is done to overcome friction, energy is transferred as what?
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Study Notes
Learning Intentions and Success Criteria
- Students are aiming to understand and calculate the work done by a force.
- Success criteria include explaining work in science, linking work to energy and calculating work done by a force.
Key Words
- Work
- Energy
- Distance
- Force
Equations
- Kinetic Energy (KE): KE = 1/2 * m * v^2 (where m = mass and v = velocity)
- Gravitational Potential Energy (GPE): E = m * g * h (where m = mass, g = gravitational field strength, and h = height)
- Elastic Potential Energy: 0.5 * spring constant * (extension)^2
- Work Done: W = F * s (where W = work done, F = force, and s = distance moved in the direction of the force)
Units
- Work done is measured in Joules (J)
- Force is measured in Newtons (N)
- Distance is measured in metres (m)
Energy Transfer and Friction
- When a force moves an object, energy is transferred to the object.
- Work is done on the object.
- Energy transferred equals work done.
- Whenever work is done to overcome friction, energy is transferred as heat.
- As an example, brake pads on a car get hot due to the transfer of kinetic energy into heat energy when the pads are applied over time to stop the car.
Example Calculations
- Students should understand how to calculate work done using the formula W = F * s. For example, a cyclist using a constant braking force of 140N to stop over a distance of 24m requires a calculation of 3360J.
- Similar example calculations are included in the slides giving further examples.
Additional Notes
- The notes highlight the link between work and energy, defining work as the transfer of energy.
- The relationship is explicitly demonstrated.
- Identifying the fundamental units for various physical quantities such as temperature, mass, pressure, force, volume, and distance is crucial. Examples of units are °C for temperature, kg (kilograms) for mass, Pa (Pascals) for pressure, N (Newtons) for force, m³ (cubic meters) for volume and m (meters) for distance.
- An understanding of how to apply the formula for calculating force based on rearranged equations is necessary.
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Description
This quiz focuses on understanding work done by forces and its relationship to energy. Students will calculate work using relevant equations and units, such as Joules and Newtons. Key concepts include kinetic energy, gravitational potential energy, and elastic potential energy.
