Posts Tagged ‘gravity’


Isaac Newton, The Great Plague and how he filled in his Time!

March 18, 2020

I am grateful to Jeff Jacoby and his column, Arguable, in the Boston Globe for reminding me of how Isaac Newton filled in his time when he went into self-isolation during The Great Plague of London in 1665-1666.

He spent time thinking and the results were astounding!!!!!



Best Ever Fun with Algebra

June 9, 2016

Mathspig gravity plane

We all know about gravity. We worry about gravity.


If someone holds a pen in your hand like the gif below, then drops it,

I bet, if you keep your hand in the one position, that you can’t grab it!!!!

The maths is soooo beautiful.


All objects and bodies drop at the same rate of acceleration, g = 9.8 m/sec2

d = distance travelled by falling object (m)

t = time taken (sec)

pen drop formula 1

pen drop formula 2

You can test your reaction time on THE REACTION TIME CLOCK HERE.


2. One Rule Aerial Skiers Cannot Break

January 23, 2014

Aerial skiers aim for height rather than length. Their aerial flight times are much smaller than ski jumpers so air resistance has minimal impact.

In fact, there is one law the aerial skiers cannot break. It is the law of gravity.

Here is an equation for  projectile motion from Wired magazine.

Screen grab from Wired Magazine

Screen grab from Wired Magazine

Here is the x-y graph for different launch angles.

trajectory wired magazine

trajectory wired magazine

You can go to this page for complete calculations. Aerial skiers twist and turn but their CENTRE OF GRAVITY must follow this graph. MOre on centre of Gravity at The Great Back Pack Attack ie.

The centre of gravity of Aerial Skiers must follow a

parabolic curve.

Aerial Parabola final 1


Aerial Parabola final 2


Rocky Maloney Winter X Games Aspen

Rocky Maloney Winter X Games Aspen