Fluid Mechanics
How does a balloon filled with helium rise in the air?
Helium is less dense than air
Give the freezing points of water in Celsius, Fahrenheit, and Kelvin
Celsius: 0°
Fahrenheit: 32°
Kelvin: 273°
This law is the relationship between electrical force, charge, and distance
Coulomb's Law
What is the density of a substance with a mass of 500 g and volume of 15 cm^3?
33.33 g/cm^3
If it is 50° Celsius, what is the temperature in Kelvin?
323° Kelvin
What is Archimedes' Principle?
An immersed body is buoyed up by a force equal to the weight of the fluid it displaces
What direction does heat move?
From a substance of high temperature to a substance of low temperature
What is an electric current?
The flow of electric charge transporting energy from one place to another
What is the power of a circuit with a current of 26 Amps and a voltage of 14 volts?
364 Joules
What is a barometer?
A device that measures atmospheric pressure
What is Bernoulli's Principle?
Where the speed of a fluid increases, internal pressure in the fluid decreases
Describe the concept of entropy
All systems tend to become more and more disordered as time goes by
Give the equation for Ohm's Law
Voltage=Current x Resistance
V=IR
If a 20 ohm resistor and a 30 ohm resistor are in a series with a current of 50 Amps, what is the voltage?
2500 Volts
What unit do we use for any type of energy?
Joules
Give the equation and units for density and pressure
Density=mass/volume (p=mv), unit: kg/m^3
Pressure=force/area, unit: N/m^2 or Pa
If water had a lower specific heat capacity, would lakes be more or less likely to freeze in winter?
More likely
What direction does an electrical field point if something is positively charged vs. negatively charged?
Positively charged: field points away
Negatively charged: field points towards
A substance with a mass of 100g absorbs 2500 J of heat, increasing the temperature from 10 °C to 70°C. What is the specific heat capacity?
.417 J/g °C
Give an example of an insulator and an example of a conductor
Insulators: glass, plastic, rubber, wood, etc.
Conductors: copper, silver, gold, aluminum, etc.
What pressure is at the bottom of a 2m pool?
(Density of water= 1000 kg/m^3)
19,600 Pa
Explain the difference between conduction, convection, and radiation
Conduction: heat transfer through molecular collisions
Convection: heat transfer by a gas or liquid
Radiation: heat transfer through electromagnetic waves
What is the difference between a series circuit and a parallel circuit?
Series circuit: devices are connected so the same electric current flows through each of them
Parallel circuit: devices are connected so voltage is the same across each one and any single one completes a circuit
A steel tower stands 250m tall on a typical day. What is the change in height if the temperature drops 25° Celsius?
(coefficient of expansion of steel is 12 x 10^-6 (Co)-1 )
.075 meters
How can a submarine rise and sink in the water?
It can take in air to change its density to move up and down. More air in the submarine, and it will rise. Less air in the submarine, and it will sink.