NEWTON'S SECOND LAW OF MOTION - F=m.a
When forces are unbalanced, an object will change direction or speed (accelerate). This is proportional to the object's mass. What does this mean?
Newton's Second Law of Motion is usually summarised as a mathematical formula (which you are given in the exam):
- Mass has to be given in kilograms (kg)
- Acceleration has to be given in metres per second per second (ms-2)
We need to be able to calculate the force of an object when given its mass and acceleration.
NCEA 2018
We also need to rearrange this equation to find the acceleration (or mass):
Weight and Mass
The most obvious application of Newton's Second Law of Motion is when we compare and contrast mass and weight.
Weight is actually a force. It is the pull of gravity on an object (or on you) towards the Earth (or whatever planet/moon you may be standing on...
This looks very similar to F=m.a. That is because "g" is effectively a form of acceleration.
You are told to use "g = 10 Nkg-1" in your exams (it is written on the front page of the exam paper, with the equations you might need)
