08092021 Gravity and Space Gravity 08092021 Gravity is
- Slides: 7
08/09/2021 Gravity and Space
Gravity 08/09/2021 Gravity is an attractive force that affects anything with mass: Note that this force goes both ways – the Earth is attracted to us.
Gravity 08/09/2021 Gravity depends on 2 things: 1) The mass of the objects F If you double the mass of one object you double the force 2 F 2) The distance between them If you double the distance the gravitational force divides by 4… F F/4
Weight vs. Mass 08/09/2021 Earth’s Gravitational Field Strength is 10 N/kg. In other words, a 1 kg mass is pulled downwards by a force of 10 N. W Weight = Mass x Gravitational Field Strength (in N) (in kg) (in N/kg) M g 1) What is the weight on Earth of a book with mass 2 kg? 2) What is the weight on Earth of an apple with mass 100 g? 3) Dave weighs 700 N. What is his mass? 4) On the moon the gravitational field strength is 1. 6 N/kg. What will Dave weigh if he stands on the moon?
Rockets When a rocket flies away from Earth the force needed to keep it accelerating decreases: 08/09/2021 _____ force needed here This is because… 1) As the rocket gets further away from Earth the force of ______ decreases. 2) As the rocket burns fuel it gets _______, also decreasing the gravity downwards. Words – gravity, smaller, large, lighter
Natural Satellites Mercury Venus 08/09/2021 These planets are all satellites of the sun Earth Mars Jupiter Saturn Uranus Neptune Pluto
Artificial Satellites 08/09/2021 Artificial satellites have been around for 50 years and have 3 main uses: 1) Observation (e. g. Hubble Space Telescope) – these are in orbit high above the Earth and can observe the universe without interference by the ______ 2) Communications (e. g. ___, phone, car “Sat. Nav” systems) – these satellites are in “geostationary” orbits. This means that the satellite always stays above ____ point on the Earth and takes a ______ to complete an orbit 3) Monitoring (e. g. weather, spy satellites) – these satellites have a “___ _____” orbit and may scan around the Earth several times a day Words – the same, atmosphere, low polar, TV, day
