Posted in ask uncle colin, mechanics 1.

Dear Uncle Colin I have a conceptual problem with impulse. Suppose you have a collision where your particle (of mass 1 kg) has an approach speed of 4m/s, changes direction, and leaves with a speed of 3m/s. That's an impulse of -7 units, and the ball slows down from 4m/s

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Posted in ask uncle colin, mechanics 1.

Dear Uncle Colin, One of my students recently attempted the following question: "At time $t=0$ particle is projected upwards with a speed of 10.5m/s from a point 10m above the ground. It hits the ground with a speed of 17.5m/s at time $T$. Find $T$." They used the equation $s

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Posted in ask uncle colin, mechanics 1.

Dear Uncle Colin, I'm struggling to make sense of questions about moments in M1. Can you help? -- Failing Equilibrium-Related Moments... All Torque! Hi, FERMAT! That's a bit more general than the kind of question I usually answer, but no matter! Here’s the briefest theory of equilibrium I can come

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Posted in integration, mechanics 1.

Most of the suvat equations are pretty easy to derive, as soon as you realise acceleration ($a$, assumed constant) is the derivative of velocity ($v$) with respect to time, and velocity is the derivative of position ($s$), also with respect to time. For example: $ a = \diff{v}{t}$ $ \int_0^t

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Posted in mechanics 1, overanalysing cbeebies.

"Things bounce six times higher on the moon!" James Corden, narrating Little Charley Bear I have some serious problems with the quality of the physics shown on CBeebies. I'm happy to accept anthropomorphised animals, the idea that all of the presenters live in the CBeebies house, and I'll even entertain

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Posted in mechanics 1.

A student asks: Hi, I am currently doing Mechanics at college and I am finding it very confusing. What can I do to help get my head around the work? This is another slightly-hard-to-answer question; because I don't know the student, or what s/he is struggling with, it's really hard

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Posted in mechanics 1.

This piece was entirely rewritten 2017-06-20 in response to a correction by Adam Atkinson. A friend of a friend stated: "... the planets exert an enormous influence on the tides..." ... and that set my oh-no-they-don't-o-meter. Let's have a look, shall we? You might think - as I did when

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Posted in mechanics 1.

At the 1939 World’s Fair, San Francisco Seals catcher Joe Sprinz tried to catch a baseball dropped from the Goodyear blimp 1,200 feet overhead. Sprinz knew baseball but he hadn’t studied physics — he lost five teeth and spent three months in the hospital with a fractured jaw. - from

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Posted in mechanics 1, vectors.

OK, so you've got to grips with the SUVAT equations, you're on top of resolving forces, you understand that $F=ma$ and you have M1 under control... only for them to start throwing $\bi$s and $\bj$s around. Who ordered those? Maybe you have a vague recollection of vectors from GCSE -

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Posted in mechanics 1, mechanics 2, space.

The gravitational slingshot is something I'd heard about but had never bothered to look up - until now. It sounded like magic: you fire a spaceship towards a planet and (then a miracle occurs before) it comes out moving faster. It's how the Voyager spacecraft picked up enough speed to

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