UNIT 1 - Dynamics Flashcards
What is newtons 1st law
An object remains at rest or constant speed unless acted upon by an external force
What is newtons second law
The rate of change of momentum of an object is proportional to the resultant force acting on it, and takes place in the direction of that force
F = MA
What is Newtons 3rd law?
Every action has an equal and opposite reaction
What does force mean and how does it relate to momentum
A push or pull acting on a body causing motion of a body
Can be defined as a change of momentum per unit time
F = change in momentum/time
(Newtons, N)
Define resultant force
The vector sum of the forces on the object
What is mass?
What is unit of mass?
Does it stay the same?
-A measure of matter
-kilograms (kg)
-always the same
What is weight?
What is units of weight?
Does it stay the same?
-A force due to gravity
-Newtons (N)
-Changes depending on gravitational field
What is equation for weight
Weight = mass x gravity
W = mg
(N) = (kg)(ms⁻²)
What causes gravity
The attraction of mass between two objects
(Causing them to accelerate to each other resulting in the curvature of space-time around massive objects) <— just to understand
Define linear momentum
It is the product of its mass and its velocity
P = mv
How does the direction of momentum relate to the direction of velocity
They are the same, direction of the momentum is in the same direction as the velocity
Define Newton
1 newton is the force required to accelerate a mass of 1kg by 1ms⁻² in the direction of the force
What is the principle of conservation of momentum
The vector sum of the momentum of bodies in a system stays constant even if forces act between the bodies, provided there is no external resultant force
Define terminal velocity
The constant and maximum velocity, when resistive forces acting on object is equal and opposite to accelerating forces acting on object.
What is elastic collision
A collision in which there is no change in total kinetic energy
