Gravitational potential energy is the energy possessed by an object due to its position in a gravitational field. It represents the work done against gravity to bring an object to a certain height above a reference point, typically the Earth's surface. This form of potential energy is crucial in understanding the behavior of objects in gravitational fields and plays a significant role in various physical phenomena, from the motion of planets to the design of roller coasters.
Formula
The formula for gravitational potential energy is:
\[ PE = m \times g \times h \]
Where:
\( PE \) is the gravitational potential energy (in Joules, J)
\( m \) is the mass of the object (in kilograms, kg)
\( g \) is the gravitational acceleration (in meters per second squared, m/s²)
\( h \) is the height above the reference point (in meters, m)
Calculation Steps
Let's calculate the gravitational potential energy for an object lifted above the Earth's surface:
Given:
Mass (\( m \)) = 5 kg
Gravitational acceleration (\( g \)) = 9.8 m/s² (approximate value on Earth's surface)
Height (\( h \)) = 10 m
Apply the gravitational potential energy formula:
\[ PE = m \times g \times h \]
Substitute the known values:
\[ PE = 5 \text{ kg} \times 9.8 \text{ m/s²} \times 10 \text{ m} \]
Perform the calculation:
\[ PE = 490 \text{ J} \]
Example and Visual Representation
Let's visualize the gravitational potential energy of an object lifted above the Earth's surface:
This diagram illustrates:
The Earth's surface (blue line)
The height (\( h \)) above the surface (green dashed line)
The object with mass (\( m \)) (yellow circle)
The gravitational potential energy (\( PE \)) represented by the red arrow
The gravitational field acting on the object (not shown, but implied)
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