A thing that often causes a little confusion is the distinction between energy (the capacity to do work – measured in joule) and forces (which are simply pushes or pulls – measured in Newton). It is very important to read exam questions very carefully to avoid using the wrong one. Energy There are three forms …
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Series:Forces
Forces v Energy (Part II)…
The next thrilling instalment in the ‘Forces v Energy‘ series – who will win? Well, neither because they are totally different things so they cannot have any sort of competition or conflict. It would be like saying ‘Custard v Empathy’ – which will win? Forces Forces are measured in Newton. Forces cause objects to speed …
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Free Fall…
New Scientist recently featured an article about a wingsuit flyer who plans to be the first to land from a freefall jump without a parachute. A wingsuit increases the jumper’s cross-sectional area so there is more air resistance (drag) and so he falls more slowly. If he is sufficiently skilful he can perform aerial stunts such as …
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Felix Baumgartner – Crazy Name, Crazy Guy…
I am sure you all remember 1960 (!) when Joe Kittinger jumped from an altitude of 31,333 metres setting an unbroken record for the highest parachute jump. Just to put that in persective, a jumbo jet flies at about 12,000 metres. Now, a base jumper called Felix Baumgartner is planning to jump from 36,575 metres. …
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Force & Linear Motion…
Time, Distance & Speed The average speed of a moving object is the distance it travels divided by the time it takes. At CE, this will usually be calculated in metres per second (m/s). The equation to use is… speed = distance ÷ time (or s=d/t) You may also need to calculate distance or time, …
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Big Load Of Nothing…
Your weight is determined by your mass and the pull of gravity. On Earth, gravity is about 9.8 N/kg (usually rounded off as 10 N/kg). The force of gravity causes objects to accelerate towards the centre of the Earth at 9.8 m/s/s (m/s/s is sometimes written as m/s2 or ms-2). In a vacuum, two objects …
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The Dzhanibekov Effect…
Also known as the Tennis Racket Theorem. Or intermediate axis theorem. When a gyroscope spins it stays upright because the spinning weight at its core resists any attempts to knock it off its access. This is called rotational inertia. Inertia refers to the tendency for moving objects to remain moving or stationary ones to remain …
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Pressure…
I have never really written much about pressure on the blog. Perhaps it has always seemed a little dull but questions do come up about pressure so I ought to have a go. It ties in nicely with the posts about forces because pressure is force applied per square centimetre. At C.E. pressure will always …
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