Chapter 4. Making Sense of the Universe: Understanding Motion, Energy, and Gravity. Describing Motion. Speed: How Fast. Velocity: How fast in which direction. Acceleration: How fast and in which direction velocity changes. Sometimes, acceleration is a constant.
Making Sense of the Universe:
Understanding Motion, Energy, and Gravity
Notice that the V arrow gets longer while the g arrow does not. It remains constant in length and direction.
V = 0m/s
t = 0 seconds
V(t) = V(0) + g(t)
V(2sec) = 0 + (10m/s2)(2s)
V(2sec) = 20m/s
V = ?
t = 2 seconds
On the Earth, the acceleration due to gravity is ~ 10m/s2 (9.8 m/s2).
p – linear momentum
p = mV
Example: If m = 10kg and V = 10m/s (East)
P = (10kg)(10m/s) = 100 kg m/s (East)
Highest high tides.
Lowest low tides.
It can be shown, by conservation of angular momentum, that the radial distance of the moon must increase as the rotation rate of the Earth decreases by tidal friction.
G = 6.67 x 10-11 m3/kg s2
M = Mass of the planet
R = Radius of the planet
We can calculate the kinetic energy of any moving object with a very simple formula:
KE = ½ mv2
m : Mass of the object. v: Speed of the object. KE: Kinetic energy measured in Joules.
Same Temperature, and more thermal energy.
Law of Conservation of Energy
Finally, at 100oC (STP), the water molecules have enough thermal energy to break free from one-another.
Evaporation begins with the production of steam (water vapor).Phases of Matter – example: water
The water remains a liquid over a large temperature range.
As the temperature increases, the water becomes a liquid (liquid water)
Below 0oC (32oF), water is a solid (ice)
Ref: PJ Brucat (University of Florida)
If the electron gains enough energy, it can escape the atom completely and we have an ionized atom.
If the electron gains energy, it becomes “smeared out” over a greater volume.
When the atom contains the smallest amount of electric potential energy, we say that the atom is in the ground state.
Any height is possible
Only discrete “Quantized” step heights are possible.