Physics Revision Flashcards
What force acts upon the rocket during take off?
Thrust
Forces that keep a satellite in orbit…
Velocity and gravitational pull from the earth.
Name the three different orbits
Geostationary orbit, Low Polar orbit and Low Earth orbit.
Name three uses of satellites…
Telecommunications, navigation, monitoring the weather.
Explain the Big Bang Theory…
The Big Bang theory was a theory that earth started from a very small fireball of infinite density that exploded and intense heat and light flew out. After 300,000 years, temperatures dropped enough for atoms to form. Clouds of hydrogen and helium gas also formed. The universe started expanding. Several billion years later matter began to contract creating stars and galaxies.
Give a strength and a weakness of the expanding universe balloon model.
Strength: Gives a good visual idea of the universe expanding and represents something we cannot see directly.
Weakness: The balloon has a limit when it pops.
When do scientists use mathematical models?
When its not possible to do an experiment to collect data.
Three factors needed for there to be a chance of life existing somewhere other than the earth.
Right temperature, liquid water, atmosphere with oxygen.
Suggest why it is likely that there is life in other places in the Universe.
There are billions of planets in the Universe, habitable zones have been found with right temperature, liquid water, atmosphere with oxygen.
Which parts of the Earth do these satellites pass over?
Geostationary orbit: Equator
Low Polar orbit: North and South Pole
Low Earth orbit: Any
How long does it take these satellites to complete one orbit?
Geostationary: 24 hours
Low Polar: Less than 24 hours
Low Earth: Between 90 minutes and 2 hours
Does the satellite stay above the same point on the earth all the time?
Geostationary: Yes
Low Polar: No
Low Earth: No
What are some risks of space missions?
Solar flare, top of rocket could explode, rely on parachutes to slow their descent.
What is Solar Flare?
Process that produces a large amount of radiation emitted by the sun.
One benefit of a space programme.
Health and medicine
Old theories…
People in India believed the earth was flat and that it was supported by 12 pillars.
People in Thailand believed the earth was supported by the back of a turtle.
People in Greece believed the earth is the centre of the Solar System.
What was the Geocentric model?
A theory that the earth is the centre of the Solar System and the planets and the sun were revolving around it.
What is the heliocentric model?
A theory that the Sun is at the centre of the Solar System and the planets revolve around it.
What is accuracy?
The accuracy of a measurement is how close a result comes to the true value.
What is precision?
Precision is how consistent the results are when measurements are repeated.
What is repeatable
A measurement is repeatable if the same person repeats the experiment using same same method and same equipment and gives similar results.
What is reproducible?
A measurement is reproducible if Another person can get the same results.
What is the independent variable?
Thing we change in experiment
What is the dependent variable?
Measure variable
What is the control variable?
Thing we keep the same
What is the resolution of a measuring instrument?
Resolution is the smallest change in the quantity being measured that can be detected by an instrument.e.g. a typical mercury thermometer will have a resolution of 1°C, but a typical digital thermometer will have a resolution of 0.1°C.
