knowt logo

Science 10 - Physics - Part 1

4 key principals

  • Energy & Conservation of Energy

    • Energy calculations/transformations

  • Work

    • W = Fdcosθ,

    • W = ∆E

    • Positive vs Negative Work

  • Efficiency

    • Eff = Wo/Wi* 100% = Eo/Ei* 100%

  • Newton’s Laws & Force Body Diagrams

    • Inertia, F = ma, Opposite and equal reaction

Energy & Conservation of Energy:

- Types of energy: Gravitational Potential, Kinetic, Mechanical, Solar, Thermal (etc)

  • Ep = mgh ← work done against gravity

    • E = Joules (J), m = Mass (kg), g = Gravity (9.81 m/s²), h = Height (m)

  • Ek = ½mv²

    • v = Speed (m/s)

  • Em = Ep + Ek

    • mgh + ½mv²

  • Emi = Emf

    • Epi + Eki = Epf + Ekf

- First Law of Thermodynamics/Conservation of Energy: Energy cannot be created or destroyed, only transformed from one type to another

- Conservation of Mechanical Energy: In an isolated system, all energy transfers are 100% efficient (nothing gets lost to friction, thermal, etc)

  • Isolated, Closed, Open systems

    • No changes, energy changes, everything changes

- Transformations of energy in machines

  • i.e.) Kinetic to Potential going up a hill on a bike

Work:

- A change in energy

  • Positive vs Negative Work

    • Putting energy into the system (positive) or taking energy out of the system (negative)

- Calculated 2 ways, W = Fdcosθ or W = ∆E

  • W = Fdcosθ

    • W = Work (J), F = Force (N), d = displacement or distance (m), cosθ = Angle of displacement (θ=0°=1, θ=90=0°, θ=180°=-1)

      • F = ma

    • Cannot be used when object is on angle other than 0, 90, or 180

  • W = ∆E

    • W = Ef - Ei

      • Use when object on slants or when no specific force is given

Efficiency:

- A calculation of how much energy is lost to friction

  • Eff = Wo/Wi* 100% = Eo/Ei* 100%

- Efficiency cannot be greater than 100% (Second Law of Thermodynamics)

  • Can only be calculated using negative work

    • Positive work would result in percentage >100%

Newton’s Laws & Force Body Diagrams:

- Newton’s Laws:

  • Inertia

    • Tendency of an object to resist change in motion (stay at rest or stay in motion)

    • More mass = more inertia

    • Not a force, rather a property of mass

  • F = ma

    • a = acceleration (m/s²)

  • Every action is met with an equal and opposite reaction (balanced forces)

    • Solid surfaces push back with equal force to what they are being pushed by

- Force Body Diagrams:

  • Force Friction

    • Force that opposes motion (slows things down, usually points in opposite direction of Force Applied)

  • Force Applied

    • Force caused by a outside push/pull, must be in direct contact with the object to be on diagram. Can be multiple

  • Force Normal

    • Force exerted by solid surfaces, point perpendicular to surface object is resting on. Can be multiple

  • Force Gravity

    • Force exerted by the earth. Always points straight down

  • Force Tension

    • Force exerted by stress on objects (such as ropes). Can be multiple

LT

Science 10 - Physics - Part 1

4 key principals

  • Energy & Conservation of Energy

    • Energy calculations/transformations

  • Work

    • W = Fdcosθ,

    • W = ∆E

    • Positive vs Negative Work

  • Efficiency

    • Eff = Wo/Wi* 100% = Eo/Ei* 100%

  • Newton’s Laws & Force Body Diagrams

    • Inertia, F = ma, Opposite and equal reaction

Energy & Conservation of Energy:

- Types of energy: Gravitational Potential, Kinetic, Mechanical, Solar, Thermal (etc)

  • Ep = mgh ← work done against gravity

    • E = Joules (J), m = Mass (kg), g = Gravity (9.81 m/s²), h = Height (m)

  • Ek = ½mv²

    • v = Speed (m/s)

  • Em = Ep + Ek

    • mgh + ½mv²

  • Emi = Emf

    • Epi + Eki = Epf + Ekf

- First Law of Thermodynamics/Conservation of Energy: Energy cannot be created or destroyed, only transformed from one type to another

- Conservation of Mechanical Energy: In an isolated system, all energy transfers are 100% efficient (nothing gets lost to friction, thermal, etc)

  • Isolated, Closed, Open systems

    • No changes, energy changes, everything changes

- Transformations of energy in machines

  • i.e.) Kinetic to Potential going up a hill on a bike

Work:

- A change in energy

  • Positive vs Negative Work

    • Putting energy into the system (positive) or taking energy out of the system (negative)

- Calculated 2 ways, W = Fdcosθ or W = ∆E

  • W = Fdcosθ

    • W = Work (J), F = Force (N), d = displacement or distance (m), cosθ = Angle of displacement (θ=0°=1, θ=90=0°, θ=180°=-1)

      • F = ma

    • Cannot be used when object is on angle other than 0, 90, or 180

  • W = ∆E

    • W = Ef - Ei

      • Use when object on slants or when no specific force is given

Efficiency:

- A calculation of how much energy is lost to friction

  • Eff = Wo/Wi* 100% = Eo/Ei* 100%

- Efficiency cannot be greater than 100% (Second Law of Thermodynamics)

  • Can only be calculated using negative work

    • Positive work would result in percentage >100%

Newton’s Laws & Force Body Diagrams:

- Newton’s Laws:

  • Inertia

    • Tendency of an object to resist change in motion (stay at rest or stay in motion)

    • More mass = more inertia

    • Not a force, rather a property of mass

  • F = ma

    • a = acceleration (m/s²)

  • Every action is met with an equal and opposite reaction (balanced forces)

    • Solid surfaces push back with equal force to what they are being pushed by

- Force Body Diagrams:

  • Force Friction

    • Force that opposes motion (slows things down, usually points in opposite direction of Force Applied)

  • Force Applied

    • Force caused by a outside push/pull, must be in direct contact with the object to be on diagram. Can be multiple

  • Force Normal

    • Force exerted by solid surfaces, point perpendicular to surface object is resting on. Can be multiple

  • Force Gravity

    • Force exerted by the earth. Always points straight down

  • Force Tension

    • Force exerted by stress on objects (such as ropes). Can be multiple

robot