Flashcards in Physics IGCSE Deck (133)
What are the units of gravitational field strength?
N/kg or m/s^2
average speed =
speed = distance/time
How do you determine the displacement from a velocity-time graph?
Area under the curve
What are the effects of a force?
change in velocity over time (acceleration); change in shape
What is friction?
A force which opposes motion
Describe the forces acting on falling objects and describe how they reach terminal velocity
The object initially accelerates toward the Earth due to the gravitational force. As the object's velocity increases, so too does its air resistance. Eventually, the force of air resistance = gravitational force, so the forces will be balanced. According to Newton's 1st Law, unless acted on by a force, an object will travel at constant velocity
Stopping distance =
s.d. = thinking distance + braking distance
What factors affect thinking distance?
Metal condition of driver; tiredness; influence of drugs; alcohol; medication; level of concentration
What factors affect braking distance?
speed; road conditions; tyre conditions; car mass; brake conditions
What is the centre of gravity?
the point within something at which gravity can be considered to act
Moment = Force x Perpendicular distance
What is Hooke's Law?
The extension of an elastic material is proportional to the force applied until the material reaches its elastic limit
What is an elastic material?
A material which will retain its original shape after a force which has been deforming it has been removed
What celestial body do comets orbit?
How do planets orbit the Sun?
In nearly circular orbits
Describe the orbit of a comet
Comets have very elliptical, elongated orbits. They travel much faster when moving near to the Sun, because the gravitational force is much stronger (the force is inversely proportional to the square of the distance from the centre of gravity)
orbital speed =
o.s. = 2πr/T
What is the universe?
Collection of billions of galaxies
What is the Milky Way galaxy?
Our galaxy; a collection of billions of stars
What is the solar system?
Collection of all the celestial bodies (planets, natural satellites, comets, asteroids etc.) which orbit the Sun
What is current measured in?
What is charge measured in?
What is energy measured in?
What is resistance measured in?
What is potential difference measured in?
What is power measured in?
What does current in a resistor cause?
Transfer of electrical energy to heat energy and an increase in temperature (e.g. in a kettle's element)