### Newton's second law of motion explains how the force needed to move an object is related to its mass and the acceleration created.

Sailors push their car in an unusual race in San Diego. |

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**How much effort does it take to push a car? **

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**It depends on how heavy the car is, right?**

Other sailors almost run with their car. |

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In this race, the teams push their cars to the finish line!

Pushing your car faster would require more effort, wouldn't it?

### This is what Newton's Second Law is all about.

*You can learn more at the links below.*

*Introduction to F=MA*

Video Lesson

Study Jams Video and Quiz

The Second Law at Cyberphysics

Newton's Laws in the NFL

Virtual Lab

Second Experiment

Why Newton Is Credited With Discovery Of ‘Second Law Of Motion’ When He Did Not Discover It ?

ReplyDeleteNEWTON HAD NOT GIVEN THE SECOND LAW OF MOTION, WHICH IS TAUGHT RIGHT SINCE 9TH CLASS ALL OVER THE WORLD.

It is clear from the study of the Principia published in 1687. At page 19 of the Principia Newton has given three laws of motion. Link to original the Principia is below.

(i) LAW AS IN NEWTON’S PRINCIPIA

In the simplest possible words Newton stated second law of motion ( as in the Principia) as

‘force is dependent of change in velocity’ or force is proportional to change in velocity. In original words as in the Principia

‘“The alteration of motion is ever proportional to the motive force impress'd; and is made in the direction of the right line in which that force is impress'd.”

Mathematically, F = (v-u)

(ii) LAW AS TAUGHT RIGHT FROM SCHOOL

Now in school level text books the law can be stated as

force is dependent on ‘Rate of change of momentum.’ Or force is proportional to ‘Rate of change of momentum.’, which is entirely different.

So we reach the same law all over the world right from 9th-10th class as

“The rate of change of momentum is proportional to the motive force impress'd; and is made in the direction of the right line in which that force is impress'd.”

Mathematically, in the simplest way it means

F= m(v-u)/t =ma

WHY THE DIFFERENCE ?

No body knows who discovered F=ma and associated it with Newton. It is open riddle. It is also discussed in American Journal of Physics and in book “Beyond Newton and Archimedes”.

www.AjayOnLine.us

The links to Newton’s the Principia, BOOK I, 1687 is below ( see page 19).

http://books.google.co.in/books?id=Tm0FAAAAQAAJ&pg=PA1&redir_esc=y#v=onepage&q&f=false