Lecture 5 Flashcards
What is Newton’s First Law?
An object moves at constant velocity unless a net force acts to change its speed or direction
What is Newton’s Second Law?
F=ma
What is Newton’s Third Law?
For every force, there is always an equal and opposite reaction force
What is Noether’s Theorem (simplified)?
Conservation laws arise from symmetries in physical space as long it is continuous and smooth
What is the conservation of momentum?
The total momentum of interacting objects cannot change unless and external force acts on them.
Interacting objects exchange momentum through equal and opposite forces
What is the conservation of angular momentum?
Angular momentum=mvr
The angular momentum of an object cannot change unless an external torque acts on it. The Earth experiences no torque so its orbit will continue indefinitely
What is the conservation of energy?
Energy can neither be created nor destroyed
What are the 3 types of energy?
-kinetic
-radiative (light)
-potential
How does gravitational potential energy in gas clouds change?
In space a gas cloud has more gravitational energy when it is spread out. When a cloud contracts it converts gravitational energy to thermal energy
What is the conservation of mass-energy?
E=mc^2
Concentrated energy can spontaneously turn into particles.
Energy can neither be created nor destroyed. It can change form or be exchanged between objects
What does gravitational potential energy depend on?
-the object’s mass
-strength of gravity
-distance that the object could potentially fall
What is kinetic energy (thermal energy)?
The collective energy of many particles
Note: temperature is the average kinetic energy
