- Newton's universal law of gravitation
- Every mass attracts every other mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.
- Gravitational field
- A region around a mass in which another mass experiences a gravitational force of attraction.
- Gravitational field strength
- The gravitational force acting on each kilogram of mass at a point in a field; measured in newtons per kilogram (N kg⁻¹).
- Kepler's laws
- Three laws describing planetary motion: orbits are ellipses, a line to the planet sweeps equal areas in equal times, and the square of the orbital period is proportional to the cube of the orbital radius.
- Satellite
- An object that orbits a larger body, such as the Moon around the Earth or a man-made satellite kept in orbit by gravitational force.
- Geostationary orbit
- An orbit above the equator in which a satellite has a period of 24 hours, so it appears to stay above the same point on the Earth's surface.
- Escape velocity
- The minimum velocity an object needs to completely escape the gravitational pull of a planet or other body.
- Orbital velocity
- The velocity a satellite must have to stay in a stable orbit at a given radius, where gravitational force provides the centripetal force.
- Universal gravitational constant
- The universal constant G in Newton's law of gravitation, with a value of about 6.67 × 10⁻¹¹ N m² kg⁻².
- Centripetal force
- The net force directed towards the centre of a circle that keeps an object moving in a circular path, such as a satellite in orbit.
What "Gravitation" terms cover
This group collects the 10 SPM Physics terms in Gravitation. Getting these definitions exactly right is some of the cheapest marks in Paper 2, a "define" or "state" question wants one precise sentence with the correct unit.
The key terms to get right
- Newton's universal law of gravitation, Every mass attracts every other mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.
- Gravitational field, A region around a mass in which another mass experiences a gravitational force of attraction.
- Gravitational field strength, The gravitational force acting on each kilogram of mass at a point in a field; measured in newtons per kilogram (N kg⁻¹).
- Kepler's laws, Three laws describing planetary motion: orbits are ellipses, a line to the planet sweeps equal areas in equal times, and the square of the orbital period is proportional to the cube of the orbital radius.
- Satellite, An object that orbits a larger body, such as the Moon around the Earth or a man-made satellite kept in orbit by gravitational force.
- Geostationary orbit, An orbit above the equator in which a satellite has a period of 24 hours, so it appears to stay above the same point on the Earth's surface.
- Escape velocity, The minimum velocity an object needs to completely escape the gravitational pull of a planet or other body.
- Orbital velocity, The velocity a satellite must have to stay in a stable orbit at a given radius, where gravitational force provides the centripetal force.
- Universal gravitational constant, The universal constant G in Newton's law of gravitation, with a value of about 6.67 × 10⁻¹¹ N m² kg⁻².
- Centripetal force, The net force directed towards the centre of a circle that keeps an object moving in a circular path, such as a satellite in orbit.
How this vocabulary is examined
These terms appear as define/state items in Paper 1 and Paper 2, and inside explain and calculate questions where using the wrong word costs marks. Learn each term with its unit and one example of correct use.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)