Circular Motion & Gravitational Fields Flashcards
Define the radian.
An angle suptended at the centre of a circle where arc length is equal to the radius of the circle.
Define angular speed.
Rate of change of angular displacement by a a force.
Describe uniform circular motion.
Constant speed where acceleration is always perpendicular to velocity.
State what is meant by centripetal acceleration.
Acceleration is perpendicular to velocity.
State what is meant by a field of force.
Region of space where a particle experiences a force.
State what is meant by a line of force in a gravitaional field.
Direction of force on a small test mass.
Explain why the acceleration of free fall near the earth’s surface is approximately constant.
Near the earth’s surface, the lines are approximately parallel and so field strength is constant which means acceleration of free fall is constant.
State what is meant by a gravitational force.
Force acting between two masses.
State Newton’s Law of Gravitation.
The force between two point masses is proportional to the product of the masses and inversely proportional to the square of their seperation.
Define gravitational field.
Force per unit mass.
Define gravitational field strength.
Gravitational force per unit mass.
Explain how a satellite may be in circular orbit around a planet.
Gravitational force of attraction between satellite and planet provides centripetal force of constant magnitude on satellite about the planet.
State some features of a geostationary satellite which orbits the earth.
- In equatorial orbit
- Period of orbit is 24 hours
- Orbit above the equator
- Travels from west to east
Each planet orbits at constant speed, so explain whether the planets are in equilibrium.
No they’re not, this is because the direction of motion of each planet changes which means acceleration is present and hence there’s a resultant force.
Define gravitational potential.
Work done per unit mass in moving mass from infinity.
