Physics nptes key definitions. Newtons Law And Momentum, Circular Motion And Oscillations, Thermal Physics
Physics Unit 1: The Newtonian World
Module 1: Newton’s Law And Momentum
- Newton’s First Law – A force is necessary to change the state of rest or of uniform motion in a straight line of a body
- Momentum/Linear Momentum – The mass of an object multiplied by its velocity
- Newton’s Second Law – The rate of change of the momentum of an object is directly proportional to the resultant net force acting upon it
- One Newton is the force that gives a mass of one kilogram an acceleration of one metre per second each second
- Mass – The inertia of an object/how difficult it is to accelerate an object
- Weight – The gravitational force the Earth exerts on an object, pulling it towards the ground
- Newton’s Third Law – When body A exerts a force on body B, then body B exerts on body A force that is equal, opposite in direction and of the same type
- The Principle Of Conservation Of Momentum – In any direction, in the absence of external forces, the total momentum of a system remains constant
- Elastic Collision – No momentum or kinetic energy is lost
- Inelastic Collision – Momentum is conserved, but kinetic energy is not
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Quality of writing
The candidate uses technical terms accurately and clearly demonstrates a good understanding of this topic. In addition the language used to describe key terms is of the standard I would expect from a grade A/B candidate. Furthermore there are no issues with spelling or grammar and the information is displayed in a clear and coherent manner.
Level of analysis
Generally the information that the candidate has stated is accurate, though there are a few errors. For example in the first section, when stating Newton’s second law of motion, the candidate has failed to mention that the change in momentum and the net force must be in the same direction. There is also key information missing, for example the candidate fails to mention that momentum is a vector quantity, which is essential when solving problems related to the momentum of given objects, if you fail to state the direction of the velocity of an object your calculations will be incorrect. In addition to this, the section on module three is relatively short and seems to be missing some important facts such as the concept of internal energy related to state changes, a description of Brownian motion and several other points. The candidate’s work could be improved with additional details and further development of key points, for example, when discussing the definitions used for an object demonstrating simple harmonic motion, it would be appropriate to provide graphs of displacement, velocity and energy as these need to be understood and can be tested on in examinations.
Response to question
The candidate has summarised key points that are relevant to this topic. They have managed to include most of the points outlined on the specification and for the most part the information provided is extremely accurate. This demonstrates a good understanding of underlining principles.
