QCE Physics Unit 3 Topic 1

Normal Force

the force acting along an imaginary line drawn perpendicular to the surface

Uniform Circular Motion

the motion of an object travelling at a constant speed in a circle 

Average Speed

the rate of change of distance calculated by the formula average speed=distance/time

Period

the amount of time one cycle or one event takes to occur; the length of time taken for one wavelength to pass a given point; in circular motion, period refers to the time taken to complete one revolution

Centripetal Acceleration

the acceleration experienced by any object moving in a circular path directed towards the centre of motion

Centripetal force

the force acting on an object travelling in a circle that constantly either pulls or pushes the object in towards the centre of motion

Newton’s law of universal gravitation

the force of attraction between each pair of point particles that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them

Gravitational Fields

the region of space surrounding a body in which another body experiences a force of gravitational attraction

Kepler’s first law

the first law states that all planets move about the Sun in elliptical orbits, having the Sun as one of the foci

Kepler’s second Law

the second law states that a radius vector joining any planet to the Sun sweeps out equal areas in equal lengths of time

Kepler’s third law

the third law states that the squares of the sidereal periods of the planets are directly proportional to the cubes of their mean distance from the Sun