Forces and Newton's laws Flashcards
Define inertia
Reluctance of a body to change its state of motion
Define mass
(kg)
The quantity of matter in a body
Is a measure of inertia
Define linear momentum
Momentum [kg.m.s-1] = mass x velocity
Define force
Pushing or pulling action that one object exerts on another
Define a newton
A force of 1N is the force that will produce an acceleration of 1m.s-2 in a 1kg mass
Define linear kinetics
Forces which cause translational movement
Either internal - e.g. muscular forces
External e.g. gravity
What is Newton’s 1st law?
An object remains at rest or continues to move with constant momentum unless acted upon by a net force.
What is net force?
All forces that are being applied to the body
What is Newton’s 2nd law?
Rate of change of momentum of a body is proportional to the force causing it and the change takes place in the direction in which the force acts
Equation for the 2nd law
Force = mass x acceleration
What is Newton’s 3rd law?
For every action there is a reaction which is equal in magnitude but opposite in direction
Define weight
Force due to gravity
weight = mass x gravity
Define weightlessness
Not subject to a reaction force e.g. a free fall
What is the equation for drag?
-1/2pv²CDA
p = density of fluid
v = speed of object
CD = drag coefficient
A = cross sectional area
Friction equation
Ff= μN
Ff= limiting friction force
μ= coefficient of friction
N= normal reaction force
