MOMENTUM (EKS 6)
ELECTRICITY (EKS 7)
DEFINITIONS & PHENOMENA (EKS 8)
ANALYZING DATA & MATH (EKS 8)
Random (APIDA)
100
Give an example and / or draw an example for each: inelastic collision, elastic collision, explosion
Inelastic: start separate, end together
Elastic: start separate, end separate
Explosion: start together, end separate
100
A spinning / moving magnet nearby a wire, causes the electrons in the wire to do what?
Causes the electrons to move!
100
Joshua Tree vs El Segundo
Which is hotter in the day? Day: __
Which is hotter at night? Night: ___
Day: JT is hotter (77/49)
Night: ES is hotter (64/58)
100
Why do most objects start around 21-23°C in our experiments?
Because that's room temperature!
100
What does APIDA stand for?
Asian Pacific Islander Desi American
200
In space, an asteroid explodes in two pieces. A small chunk of it (m1), 900 kg, flies off 20 m/s to the right. The rest of it flies off to the left at 1.5 m/s. What is the mass of the other chunk (m2)?
(m1)(v1f) = - (m2)(v2f)
(900 kg) (20) = - (-1.5) (m2)
m2 = 12000 kg
200
6.7 x 1018 electrons pass through a lightbulb in one second. Each electron has a charge of 1.6 x 10-19 C.
CALCULATE THE TOTAL CHARGE that passes through a lightbulb in one second
(6.7 x 1018) (1.6 x 10-19 C)
(6.7) (1.6) x 10-1
10.72 x 10-1
1.072 C
200
Which demographics does Urban Heat Island (UHI) affect the most?
POC and poor
200
Convert 45°C to Fahrenheit
°F = 9/5 (°C) + 32
°F = 9/5 (45) + 32
°F = 81 + 32 = 113
200
Name four teachers at DVC that are part of APIDA?
Lolita, Caleb, T, Donald
300
A man’s head (which is 5kg) is flying towards his car’s air bag at 15 m/s. If the collision time with the air bag is 0.05 seconds, what is the Force experienced by the man’s head?
FΔt = mΔv
(F)(0.05s) = (5kg)(-15m/s)
F = 1500 N
300
Draw two circuit diagrams
Diagram A: 3 resistors in series, w a battery
Diagram B: 3 resistors in parallel, w a battery
An electron must pass through all resistors in series
An electron chooses which resistor to pass through in parallel
300
Give an example for each: conduction, convection, and radiation
Conduction: things are touching
Convection: hot rises, cold sinks
Radiation: travel thru space
300
A metal watch and a skateboard start out at room temperature, but then they both go outside and start heating up under the sun. How can you tell from the graph which one has a higher specific heat capacity?
Skateboard. The curve is less steep, gains temp slower = high capacity.
300
What is boba made out of?
Tapioca / potato starch
400
Bumper car A (200kg) is going 5 m/s to the right. It elastically collides with bumper car B (300 kg), which is initially still. After the collision, bumper car A is going 1 m/s to the left, what is the velocity of bumper car B?
(m1)(v1i) + (m2)(v2i) = (m1)(v1f) + (m2)(v2f)
(200kg)(5m/s) + (300kg)(0) = (200kg)(-1m/s) + (300kg)(v2f)
1000 + 0 = -200 + 300(v2f)
1200 = 300(v2f)
v2f = +4m/s
400
A circuit has one resistor of 20Ω, and a 1.5V battery. Calculate the current.
V = IR. Voltage = (current) (resistance)
1.5 = (I) (20)
I = 1.5 / 20 = 0.075 A
400
Why are oceans such good “energy banks”? (give two reasons)
Has water (↑ SHC)
Has a lot of water (↑ size)
400
50 grams of water goes from 20°C to 27°C. The specific heat capacity of water is 4.184 J/(g*C). What is the amount of heat added to the water?
Q = mcΔT
Q = (50)(4.184)(7)
Q = 1464 J
400
Which US city has the highest percentage of Asian residents relative to its total population?"
~hint, so not NYC, because even though it has the most people, it’s not by %
Honolulu, HI: ~54.8% (Alone) / 68.2% (In combination) Fremont, CA: ~63.7% Daly City, CA: ~56.9% Milpitas, CA: ~71.3% Cupertino, CA (Home of Apple): ~70.1% Waipahu, HI: ~67.1% Monterey Park, CA: ~66.0%
500
A 0.001 kg dart is shot at 10 m/s. It hits and sticks to a toy car (with a mass of 0.025 kg) that is initially still. After the inelastic collision, the toy car and the dart move together at what velocity?
(m1)(v1i) + (m2)(v2i) = (m1 + m2)(vf)
(0.001kg)(10m/s) + (0.025kg)(0) = (0.026kg)(vf)
0.010 + 0 = 0.026(vf)
vf = 0.385 m/s
500
A circuit has two resistors in series. R1 is 20Ω. R2 is 35Ω. The battery is 9V. Calculate the current.
V = IR. Voltage = (current) (resistance)
9 = (I) (55)
I = 9 / 55 = 0.164 A
500
Which absorbs more energy from the sun on a hot day, a palm tree or a metal pothole cover?
Explain your answer
Palm tree (changes temperature less, but absorbs more heat)
-difference between temperature and heat
-heat leaves though via evapotranspiration or used in photosynthesis
500
A 100 gram cotton towel heats up. It starts at 20°C, and then 2800J of energy is added. The final temperature is not given and must be calculated. The specific heat capacity of cotton is 1.20 J/(g*°C).
Q = mcΔT
ΔT = final temp - initial temp
2800 = (100)(1.20)(ΔT)
ΔT = 2800 / 120
ΔT = 23.33°C
Final temp = 20+23.33 = 43°C
500
What percent of the population of LA is Asian? (gotta be within +or - 3% range)
12.7%