pick an earthquake either recent or in the past and write a brief news article that would go in a paper explaining where, when, can you explain tectonic setting that caused the earthquake, what kinds of damage was done, was it a deep or shallow "focus" earthquake any other information that you can find that would be exciting to put in. (100 words)
In: Physics
Occupational safety experts have developed an alternative criterion for electrical safety. They have found that shocks lasting less than 3 s will be nonlethal if the product of the voltage drop across the body, the current through the body, and the time (≤ 3.0 s) that the current flows does not exceed 13.5 V⋅A⋅s = 13.5 J. Suppose that one hand of a potential victim is grounded and the other hand touches a voltage source; suppose further that his skin resistance is negligible--a worst-case scenario.
Using the criterion above, what is the largest voltage that will not be lethal for a shock that lasts 1.2 s?
In: Physics
Your book has a section entitled "Energy Choices" and "Energy Problems" with a discussion that never includes the term "planetary overpopulation." Do you think the energy problems of the world can be solved if our human population continues to increase? Why or why not? Make a good argument! Support your idea with facts.
In: Physics
A curve of radius 40 m is banked for a design speed of 60 km/h.
If the coefficient of static friction is 0.30 (wet pavement), at
what range of speeds can a car safely make the curve?
minimum
maximum
In: Physics
Please type down (easy for me to copy and paste) your response (thoughts, ie agree or diagree and why?) after your reading the following paragraphs. (min 5 sentences, 150-200 words)
Climate change is a great environmental threat that requires attention. It exacerbates extreme weather patterns and changes in temperature, which in turn affect the livelihoods and lifestyles of people around the world. The biggest cause of climate change is the emission of CO2. One solution to climate change is the use of current renewable energy. Renewable energy is an adequate form of energy that does not require fuel. Its advantage is that it is virtually inexhaustible in duration; they are constantly replenished. However, they are limited in flow; solar energy and wind power are not always available. Another solution is nuclear power, which is a less appealing solution compared to renewable energy. Advancing technology nuclear power can increase the risk that the nuclear power will be used for malevolent purposes, such as creating weapons. Nuclear power is also dangerous in that errors in operation can lead to a disaster similar to that of Chernobyl, where a nuclear reactor explosion caused numerous deaths resulting from radiation exposure.
Bill Gates’ proposed solution for the climate change problem is TerraPower. TerraPower “breeds [the 99%, the 238] uranium as it goes along, so it's kind of like a candle” (Gates, 2010). The 238 uranium is thus essentially a “miracle battery,” storing enough fuel for the entire lifetime on the planet (Gates, 2010). I think if we depend on nuclear power for energy, there is always the risk of equipment malfunction and radiation exposure, which is extremely detrimental. Nonetheless, Gates understands the value of discovering innovative ideas through research and technology in order to benefit the public. Essentially, his wish for efficient, low cost energy is an idea worth spreading.
In: Physics
Please type down (easy for me to copy and paste) your response (thoughts, ie agree or diagree and why?) after your reading the following paragraphs. (min 5 sentences, 150-200 words)
Energy and climate is not only extremely important to the poorest, but yes I do agree that it is more important and affect them more than anyone else. It is best to acknowledge that there are people who did not know the scale or density of how much carbon is released into the atmosphere and how negatively it has impacted it. Now that fossil fuels and coals are what's essential to our everyday lives, that basically keeps our power on, it is extremely hard for us to aim to undo what has been done or even switch over to nuclear power plant just like that.
Nevertheless, if we as a people do not see climate change as a problem, our motivation in doing something about it or our aim to help improve our atmosphere is basically nonexistence. As Bill Gates said: "We need a new system, we need energy miracles". Gates have brought up 5 solutions, Solar Thermal, Solar Photovoltaic, Nuclear, Wind and Carbon Capture and Storage. I am more familiar with the solar and wind energy as being more efficient, though it will be definitely costly. Moreover, I would rather invest in solar energy because even though it may be expensive, in will still save a lot in the long run. Yes, Bill Gate is right that the sun doesn't shine all the time and the wind doesn't always blow. That is why we aim to create batteries that we store these energies for a long period of time. This is the type of investment that I rather my tax money goes into and also our focus as a society should be more towards.
In: Physics
Calcium reacts with sulfur (S8) forming calcium sulfide. What is the theoretical yield (g) of CaS(s) that could be prepared from 1.83 g of Ca(s) and 3.35 g of sulfur(s)? Enter your answer in decimal format with two decimal places and no units.
In: Physics
A four-wheel cart of mass M = 95 kg is moving along a horizontal surface with a constant velocity V = 3.5 m/s relative to the ground. A person of mass m1 = 65 kg carrying a backpack of m2 = 8 kg runs and catches up to the cart, and then jumps onto the cart. Just before landing on the cart, the person is moving parallel to the ground and the velocity of the center of mass of the system including the person, backpack and cart is VCM = 5 m/s.
What is the speed of the person just before landing on the cart?
v0 = 5.3 m/s
v0 = 12 m/s
v0 = 0.45 m/s
v0 = 7 m/s
v0 = 8.8 m/s
2)
What is the horizontal momentum of the person after landing on the cart?
pf = 325 kg m/s
pf = 455 kg m/s
pf = 228 kg m/s
3)
Compare the total kinetic energy of the system including the person, backpack and cart before the person has landed on the cart to after.
KEbefore = KEafter
KEbefore > KEafter
KEbefore < KEafter
4)
The person now holds the backpack off the back of the cart and lets go. The backpack falls to the ground. What happens to the speed of the cart when the backpack is dropped?
increases
decreases
stays the same
(Note: Answers are D, A, B, C. Please show work and reasoning.)
In: Physics
(a) How long (in s) would it take a 1.00 ✕ 105 kg airplane with engines that produce of 100 MW of power to reach a speed of 200 m/s and an altitude of 12.0 km if air resistance were negligible?
_? s
(b) If it actually takes 950 s, what is the power applied, in megawatts?
_? MW
(c)Given this power, what is the average force (in kN) of air resistance if the airplane takes 1200 s? (Hint: You must find the distance the plane travels in 1200 s assuming constant acceleration.)
_? kN
In: Physics
What is the phase shift of the TM and TE rays
reflected both externally (air to glass) and internally (glass to
air) for the situation discussed in Prob. 10?
Prob. 10 is Calculate the reflectance and transmittance for both TE
and TM modes of light incident from air at 30 onto glass of index
1.60.
In: Physics
A basketball leaves a player's hands at a height of 2.25 m above the floor. The basket is 3.05 m above the floor. The player likes to shoot the ball at a 36.0 ∘ angle If the shot is made from a horizontal distance of 12.00 m and must be accurate to ±0.32 m (horizontally), what is the range of initial speeds allowed to make the basket?
Enter your answers numerically separated by a comma.
In: Physics
You and your friend go sledding. Out of curiosity, you measure the constant angle θ that the snow-covered slope makes with the horizontal. Next, you use the following method to determine the coefficient of friction µk between the snow and the sled. You give the sled a quick push up so that it will slide up the slope away from you. You wait for it to slide back down, timing the motion. It turns out that the sled takes four times as long to slide down as it does to reach the top point in the round trip. In terms of θ, what is the coefficient of friction? draw a free body diagram for the sled going up the slope and another for the sled coming down the slope, show all work and explain in 1 - 2 sentences why it takes longer for the sled to slide down the slope than to go up the slope
In: Physics
An AC generator supplies an rms voltage of 230 V at 60.0 Hz. It is connected in series with a 0.400 H inductor, a 3.40 μF capacitor and a 206 Ω resistor.
What is the impedance of the circuit? Tries 0/20
What is the rms current through the resistor? Tries 0/20
What is the average power dissipated in the circuit? Tries 0/20
What is the peak current through the resistor? Tries 0/20
What is the peak voltage across the inductor? Tries 0/20
What is the peak voltage across the capacitor? Tries 0/20
The generator frequency is now changed so that the circuit is in resonance. What is that new (resonance) frequency?
In: Physics
Select True or False for the following statements about electromagnetic waves. The sun's radiation is most intense in the visible region. Radio waves travel in vacuum at a lower speed than the visible light. The Earth's atmosphere is quite transparent to infrared radiation. Gamma rays can be produced through electrons oscillating in wires of electric circuits. Visible light is often emitted when valence electrons change their state. A vertical automobile antenna is sensitive to electric fields polarized vertically. X-rays travel in vacuum at a higher speed than the visible light.
In: Physics
An infinitely long conducting cylinder of radius 2 cm has a linear charge density +3 μC/m is surrounded by an insulating shell of inner radius 8 cm and outer radius 12 cm. The insulating shell has a net linear charge density of +3 μC/m which may be assumed to be uniformly distributed through its volume
What is the electric potential difference (ΔV) between 12 cm and 15 cm?
What is the electric potential difference (ΔV) between 8 cm and 12 cm?
What is the electric potential difference (ΔV) between 1 cm and 5 cm?
In: Physics