# Browsing category mechanics 1

## Ask Uncle Colin: Impulse and Speed

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

## How high do things bounce on the moon?

"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

## A student asks: How can I make M1 less confusing?

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

## The pull of the planets

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

## A baseball with your name on it

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

## Dealing with M1 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 -

## How the gravitational slingshot works

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