Mechanics
The quantity that measures how much an object resists changes to its motion
What is inertia?
What is the unit of electric current?
What is the ampere (A)?
The distance between two consecutive wavecrests of a wave is called?
What is wavelength?
What is the SI unit of temperature?
What is the kelvin (K)?
Who proposed the theory of relativity?
Who is Albert Einstein?
The formula for acceleration
a = (Delta)v/(delta)t
Ohm’s Law relates voltage, current, and resistance. Write the equation.
V = IR
where V is voltage, I is current, R is Resistance
Sound waves are what type of wave — longitudinal or transverse?
What is longitudinal?
What law states that energy cannot be created or destroyed?
What is the First Law of Thermodynamics?
What particle has no charge and is found in the nucleus?
What is a neutron?
A 10 kg box experiences a net force of 20 N. What is its acceleration?
2 m/s^2.
Solution: Use F = ma, Newton's second law, and substitute accordingly.
A 12 V battery is connected to a 6 Ω resistor. What’s the current?
2 Amperes.
V = IR!
A light wave has a frequency of 5× 10^14 Hz (Hertz). What’s its wavelength in a vacuum? (Calculator active, scientific notation)
What is 6.0 x 10^-7 m?
Solution:
The wavelength of light can be found using λ=c/f (dividing the speed of light by its frequency.)
c = 299 792 458 m /s
If 500 J of heat is added to a gas and it does 200 J of work, how much does its internal energy change?
What is ΔU = +300J?
Solution:
The change in a system’s internal energy (ΔU) equals the heat added (Q) minus the work (W) done, ΔU=Q−W.
What is the energy of a photon with frequency 6 x 10^14 Hz? (Calculator active, scientific notation)
E = hf = 4 x 10^-19
Solution:
A photon’s energy depends on its frequency via E=hf, where h is Planck’s constant (6.62607015 × 10^-34 joule-seconds (J·s))
A ball is thrown straight up with an initial velocity of 15 m/s. How long until it reaches the top? (Calculator active) Assume g = 9.8 m/s^2
t = 1.53 seconds
Solution: Use the kinematic equation of constant acceleration that relates all the variables given/known. This would be the best one to use.
v(f) = v(i) + at
where v(f) = final velocity, v(i) = initial velocity, a = acceleration, and t = time.
Substitute accordingly and recognize that a = g = 9.8 m/s^2 and at the top of the ball's trajectory, the velocity (vf) is 0.
Doubling the distance between two charges does what to the electric force between them?
It decreases by a factor of 4.
Solution: This is because of Coulomb's Law, which states the force is inversely proportional to the square of the distance ( F = 1/d^2)
where F is the electric force between two charges and d is the distance between two charges
What happens to light as it passes from air into glass?
It slows down and bends toward the normal.
Solution:
When light moves from air into glass, it slows down and bends toward the normal, an imaginary line perpendicular to the surface where the light enters.
Why does metal feel colder than wood at the same temperature?
Metal is a better conductor of heat.
Solution:
Metal feels colder than wood because it conducts heat away from your hand much faster, not because it’s actually colder.
What is the process by which unstable nuclei emit radiation?
What is radioactive decay?
A car of mass 1000 kg speeds up from 10 m/s to 30 m/s in 5 s. Find the net force acting on it.
F=ma=4000N
A 3 m wire carrying 2 A of current is in a 0.5 T magnetic field perpendicular to it. Find the magnetic force.
3 Newtons
F = BIL
Why do we see colors in a soap bubble or oil slick?
Because of thin-film interference, where light waves reflect off different layers and interfere to create colors.
Solution:
Soap bubbles and oil slicks show colors because light reflects off their thin layers at slightly different depths, causing the waves to interfere and create colorful patterns.
The process in which a gas expands WITHOUT heat exchange.
What is an adiabatic process?
Solution:
In an adiabatic process, a gas changes volume and temperature without any heat entering or leaving the system (Q=0).
According to Einstein’s equation E=mc^2, how much energy is equivalent to 1 g of mass? (Calculator active, scientific notation)
What is 9×1013J9 × 10^{13} J9×1013J
What is 9 x 10^13 Joules?
Solution:
Even tiny amounts of mass can be converted into huge amounts of energy through E=mc^2, showing mass–energy equivalence.
Set m = 1 (1 gram).
E = c^2