Lift an object and you store energy in it, ready to be released the moment it falls. Raise it higher, or make it heavier, and you bank more. The store depends only on how far it rises, the strength of gravity, and its mass, not on the path it took to get there.
The change in gravitational potential energy is ΔPE = mgΔh, where m is mass, g is the gravitational field strength (about 9.8 N/kg on Earth) and Δh is the change in height. It is measured in joules.
The change in gravitational potential energy is the mass multiplied by the gravitational field strength multiplied by the change in height.
g is the gravitational field strength (about 9.8 N/kg on Earth). Only the change in height matters.
Set the mass and lift the object to different heights. The gravitational potential energy stored rises in step with both the mass and the height gained.
Four quick checks on the equation and what it depends on. Each correct answer earns XP and lights this skill on your star map.
The change in gravitational potential energy is calculated using...
The gravitational potential energy gained depends on the mass, the gravitational field strength, and...
Gravitational potential energy is measured in...
In ΔPE = mgΔh, the quantity g is the...
The defining equation and two useful rearrangements:
A 4.0 kg bag is lifted 2.5 m onto a high shelf. Taking g = 9.8 N/kg, find the gain in gravitational potential energy.
Use the change in height, measured vertically, not the distance travelled along a ramp or slope. A 10 m slope that rises 3 m vertically gives Δh = 3 m, not 10 m. And use the value of g the question gives you, whether that is 9.8 N/kg or the rounded 10 N/kg.
Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.
A 2.0 kg book is lifted 1.5 m onto a shelf. Taking g = 10 N/kg, the gain in gravitational PE is...
A 0.50 kg ball gains 20 J of gravitational PE when lifted. Taking g = 10 N/kg, the height it rises is...
A 60 kg climber goes up a 5.0 m ladder, then walks down a 2.0 m slope to a ledge. Taking g = 10 N/kg, the net gain in gravitational PE is...
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