1. Understanding Law of Gravity
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This video covers the Law of Gravitation, as Newton understood it. (hint: its actually wrong.......but works well for most situations. Einstein provides a better understanding .) |
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Gravity Variation
The value of acceleration due to gravity at the surface of the Earth varies from the usually accepted value of 9.81 m/s/s, due to a number of factors:
As a result of the above, the value of g at the surface of the Earth varies between 9.782 ms-2at the equator and 9.832 m/s/s at the poles
The value of acceleration due to gravity at the surface of the Earth varies from the usually accepted value of 9.81 m/s/s, due to a number of factors:
- The Earth’s lithosphere varies in structure, thickness and density. Thickness variations are a product of the source and history of the material. Oceanic crust is thinner than continental crust. Continental crust is thickest under mountain ranges. Density variations occur due to the presence of concentrated and large mineral deposits or petroleum gas and related liquids trapped in sedimentary rocks and structures. All of these variations can influence local values of g.
- The Earth’s globe is flattened at the poles. This means that the distance of the surface from the centre of the Earth is less at the poles, which increases the local value of g.
- The spinning Earth also affects the value of g. At the equator, the spin effect is greatest resulting in a lowering of the value of g. As you travel from the equator to the poles, the spin effect on g shrinks to zero.
As a result of the above, the value of g at the surface of the Earth varies between 9.782 ms-2at the equator and 9.832 m/s/s at the poles
pHET
This great pHET interactive allows to explore the Law of Gravitation
2. Gravity and Orbital Velocity
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What determines a satellite's orbital velocity. In essence, the gravitational field does and how high it is. Watch the video and learn more. |
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Use this interactive to explore how gravity affect orbital motion
3. Understanding Gravitational Potential energy
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Gravitational potential energy, or simply Gravitational energy is due to the work done by a gravitation field. This video discusses this concept, allowing for change in gravitational fields and shows, in a simple way how the formula is determined. All this in the context of a teddy bear |
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4. What are Kepler's Three Laws?
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Keplers' Law provides a description of how object move around a central mass. It was explained by understating of Newton's Law of Gravity
This video exams laws. |
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5. Examine satellite motion in terms of their energy
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A satellite in orbit is in motion. This means it has both gravitational potential energy (U) and kinetic energy (K). So how are they related? Watch and learn. |
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6. Examining physics of satellites using ©Spacebook
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©Spacebook is a great online tool that examines real satellites in earth's orbit. This video explains how you can use it to get a better understating of the physics involved
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7. The physics of rocket launching
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Using a Saturn V rocket and simulation data online, I examine the physics of launching, specifically acceleration, force and momentum |
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