Our Dynamic Universe Flashcards
What is momentum?
Momentum is the product of mass and velocity
What is the law of momentum?
The total momentum before a collision is equal to the total momentum after the collision
What is an elastic collision?
An elastic collision is one in which both momentum and kinetic energy are conserved
What is an inelastic collision?
An inelastic collision is one which momentum is conserved but kinetic energy is not
What should you state about any Collison regarding momentum and force?
The changes in momentum of each object are equal in size and opposite in direction.
The forces acting on each object are equal in size and opposite in direction
What is impulse?
Impulse is force x time
impulse is the change in momentum
Ft=mv-mu
The impulse of a force is equal to what?
The area under its force time graph
How does a projectile move?
A projectile moves horizontally and vertically at the same time.
it has a constant horizontal velocity and a constant vertical acceleration
What is the Doppler effect?
The Doppler effect is the change in frequency observed when a source of sound waves is moving relative to an observer
Describe the Doppler effect relative to the observer?
The source of sound moving towards the observer has a higher frequency and a source of sound moving away from the observer has a lower frequency
Light from objects moving away from us is what?
Red shifted
the wavelength is longer
The redshift of a galaxy is the what?
The change in wavelength divided by the emitted wavelength
For slowly moving galaxies red shift is what/
The ratio of the velocity of the galaxy to the velocity of light
z = v/c
What is hubbles law?
The relationship between the recession velocity of a galaxy and its distance from us?
What is the average age of the universe?
13.8 billion years
