Q 01/05

In which book did Isaac Newton first state his three laws of motion?

A) Opticks, or a Treatise of Light

B) De Motu Corporum in Gyrum

C) Philosophiæ Naturalis Principia Mathematica

D) Arithmetica Universalis

Answer · why

C) Philosophiæ Naturalis Principia Mathematica

Its title means 'Mathematical Principles of Natural Philosophy'; most people just call it the Principia.

Q 02/05

In what year was the Principia originally published?

A) 1727

B) 1705

C) 1713

D) 1687

Answer · why

D) 1687

Newton put out two more editions in his lifetime, a corrected one in 1713 and an improved one in 1726.

Q 03/05

Newton's first law says a body's natural behaviour is to move how?

A) In a straight line at constant speed

B) In a circle at constant speed

C) Toward the nearest large mass

D) Slowing gradually to rest

Answer · why

A) In a straight line at constant speed

That is the principle of inertia: left alone, a body keeps doing exactly what it is already doing.

Q 04/05

According to the first law, what is needed to change a body's state of rest or uniform motion?

A) A change in its temperature

B) A force impressed upon it

C) A change in its colour

D) The passage of time

Answer · why

B) A force impressed upon it

Newton's wording was that a body continues in its state 'unless it is compelled to change that state by forces impressed upon it'.

Q 05/05

Newton's second law says the change of motion is proportional to what?

A) The force impressed

B) The body's volume

C) The body's temperature

D) The time elapsed

Answer · why

A) The force impressed

And it happens along the straight line in which that force acts, which is why the law is written with vectors today.