Difference between revisions of "Gravitational Potential Energy Store"
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| style="height:20px; width:400px; text-align:center;" |The equation for '''gravitational potential energy''' written in symbols. | | style="height:20px; width:400px; text-align:center;" |The equation for '''gravitational potential energy''' written in symbols. | ||
+ | |} | ||
+ | |||
+ | ==Key Stage 4== | ||
+ | ===Meaning=== | ||
+ | The '''gravitational potential energy store''' is the [[Energy Store|energy stored]] in an [[object]] that is in a [[Gravitional Field|gravitional field]]. | ||
+ | |||
+ | ===About Gravitational Potential Energy=== | ||
+ | : '''Gravitational Potential Energy''' is a [[Potential Energy|potential energy]] due to the position of a [[mass]] in a [[Gravitational Field|gravitational field]]. | ||
+ | : The '''gravitational potential energy store''' of an [[object]] is related to three important factors: | ||
+ | *The [[mass]] - The greater the [[mass]] of an [[object]] the greater the '''gravitational potential energy'''. | ||
+ | *The [[Gravitational Field Strength|gravitational field strength]] - The greater the [[Gravitational Filed Strength|gravitational field strength]] the greater the '''gravitational potential energy'''. | ||
+ | *The [[height]] of the [[object]] - The greater the [[height]] of an [[object]] in a [[Gravitational Field|gravitational field]] the greater the '''gravitational potential energy'''. | ||
+ | |||
+ | ===Equation=== | ||
+ | ''NB: You must memorise this equation!'' | ||
+ | |||
+ | '' '''Gravitational Potential Energy''' = (Mass) x (gravitational field strength) x (change in height)'' | ||
+ | |||
+ | <math>E_g = m g \Delta h</math> | ||
+ | |||
+ | Where: | ||
+ | |||
+ | E<sub>g</sub> = '''Gravitational Potential Energy''' stored. | ||
+ | |||
+ | m = The [[mass]] of the [[object]]. | ||
+ | |||
+ | g = The [[Gravitational Field Strength|gravitational field strength]]. | ||
+ | |||
+ | Δh = The change in [[height]] of the [[object]]. | ||
+ | |||
+ | ===Calculating Gravitational Potential Energy=== | ||
+ | {| class="wikitable" | ||
+ | | style="height:20px; width:200px; text-align:center;" |A weight lifter lifts a 50kg [[mass]] a distance of 2.0m from the ground. Calculate the increase in '''gravitational potential energy''' of the [[mass]]. | ||
+ | |||
+ | g on Earth is 9.8N/kg | ||
+ | | style="height:20px; width:200px; text-align:center;" |A pulley is used to lift a 12 tonne [[mass]] 0.80m above the ground. Calculate the change in energy in the gravitational potential store. | ||
+ | |||
+ | g on Earth is 9.8N/kg | ||
+ | |||
+ | Give your answer correct to two [[Significant Figures|significant figures]]. | ||
+ | | style="height:20px; width:200px; text-align:center;" |During a rock slide a 320kg boulder falls from a [[height]] of 1450m to a height of 730m above sea level. Calculate the change in '''gravitational potential energy'''. | ||
+ | |||
+ | g on Earth is 9.8N/kg | ||
+ | |||
+ | Give your answer correct to two [[Significant Figures|significant figures]]. | ||
+ | |- | ||
+ | | style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' | ||
+ | |||
+ | m = 50kg | ||
+ | |||
+ | g = 9.8N/kg | ||
+ | |||
+ | Δh = 2.0m | ||
+ | | style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' | ||
+ | |||
+ | m = 12tonne = 12,000kg | ||
+ | |||
+ | g = 9.8N/kg | ||
+ | |||
+ | Δh = 0.80m | ||
+ | | style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' | ||
+ | |||
+ | m = 320kg | ||
+ | |||
+ | g = 9.8 N/kg | ||
+ | |||
+ | Δh = h<sub>2</sub> - h<sub>1</sub> = 1450 - 730 = 720m | ||
+ | |||
+ | |- | ||
+ | | style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' | ||
+ | |||
+ | <math>E_g = m g \Delta h</math> | ||
+ | |||
+ | <math>E_g = m \times g \times \Delta h</math> | ||
+ | |||
+ | <math>E_g = 50 \times 9.8 \times 2</math> | ||
+ | |||
+ | <math>E_g = 980J</math> | ||
+ | | style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' | ||
+ | |||
+ | <math>E_g = m g \Delta h</math> | ||
+ | |||
+ | <math>E_g = m \times g \times \Delta h</math> | ||
+ | |||
+ | <math>E_g = 0.80 \times 9.8 \times 12000</math> | ||
+ | |||
+ | <math>E_g = 94080J</math> | ||
+ | |||
+ | <math>E_g \approx 94000J</math> | ||
+ | | style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' | ||
+ | |||
+ | <math>E_g = m g \Delta h</math> | ||
+ | |||
+ | <math>E_g = m \times g \times \Delta h</math> | ||
+ | |||
+ | <math>E_g = 320 \times 9.8 \times 720</math> | ||
+ | |||
+ | <math>E_g = 2257920J</math> | ||
+ | |||
+ | <math>E_g \approx 2300000J</math> | ||
|} | |} |
Revision as of 18:24, 31 January 2019
Contents
Key Stage 3
Meaning
The gravitational potential energy store is the energy stored in an object that is in a gravitional field.
About The Gravitational Potential Energy Store
- The stronger the gravitational field the more energy in the gravitational potential energy store.
- The greater the mass of the object the more energy in the gravitational potential energy store.
- The greater the height of the object the more energy in the gravitational potential energy store.
Equation
The equation for gravitational potential energy written in words. |
The equation for gravitational potential energy written in symbols. |
Key Stage 4
Meaning
The gravitational potential energy store is the energy stored in an object that is in a gravitional field.
About Gravitational Potential Energy
- Gravitational Potential Energy is a potential energy due to the position of a mass in a gravitational field.
- The gravitational potential energy store of an object is related to three important factors:
- The mass - The greater the mass of an object the greater the gravitational potential energy.
- The gravitational field strength - The greater the gravitational field strength the greater the gravitational potential energy.
- The height of the object - The greater the height of an object in a gravitational field the greater the gravitational potential energy.
Equation
NB: You must memorise this equation!
Gravitational Potential Energy = (Mass) x (gravitational field strength) x (change in height)
\(E_g = m g \Delta h\)
Where:
Eg = Gravitational Potential Energy stored.
g = The gravitational field strength.
Δh = The change in height of the object.
Calculating Gravitational Potential Energy
A weight lifter lifts a 50kg mass a distance of 2.0m from the ground. Calculate the increase in gravitational potential energy of the mass.
g on Earth is 9.8N/kg |
A pulley is used to lift a 12 tonne mass 0.80m above the ground. Calculate the change in energy in the gravitational potential store.
g on Earth is 9.8N/kg Give your answer correct to two significant figures. |
During a rock slide a 320kg boulder falls from a height of 1450m to a height of 730m above sea level. Calculate the change in gravitational potential energy.
g on Earth is 9.8N/kg Give your answer correct to two significant figures. |
1. State the known quantities
m = 50kg g = 9.8N/kg Δh = 2.0m |
1. State the known quantities
m = 12tonne = 12,000kg g = 9.8N/kg Δh = 0.80m |
1. State the known quantities
m = 320kg g = 9.8 N/kg Δh = h2 - h1 = 1450 - 730 = 720m |
2. Substitute the numbers into the equation and solve.
\(E_g = m g \Delta h\) \(E_g = m \times g \times \Delta h\) \(E_g = 50 \times 9.8 \times 2\) \(E_g = 980J\) |
2. Substitute the numbers into the equation and solve.
\(E_g = m g \Delta h\) \(E_g = m \times g \times \Delta h\) \(E_g = 0.80 \times 9.8 \times 12000\) \(E_g = 94080J\) \(E_g \approx 94000J\) |
2. Substitute the numbers into the equation and solve.
\(E_g = m g \Delta h\) \(E_g = m \times g \times \Delta h\) \(E_g = 320 \times 9.8 \times 720\) \(E_g = 2257920J\) \(E_g \approx 2300000J\) |