Planet Lex is four times as massive as the Earth and has a radius four times larger than the Earth's radius. Note: You do not have to express your answers in scientific notation.

Mass of the Earth = 5.97 x 10²⁴ kg

Radius of the Earth = 6.37 x 10⁶ m

a.

What is the value of the acceleration due to gravity (in m/s²) on the surface of this planet? Round off your answer up to two decimal digits.

b.

At what altitude, h, above the surface of the Earth (in meter) is the value of the acceleration due to gravity equal to that on the surface of Planet Lex? Round off your answer in two decimal digits.

c.

If a GPS satellite of mass 2000 kg is to be placed in a circular orbit at this altitude, h, from the Earth's surface, find the value of tangential speed (in m/s). Round off your answer up to two decimal digits.

d.

Find the period of rotation (in seconds) of the GPS satellite at this altitude, h, above the surface of Earth.

e.

Find the magnitude of the centripetal force (in Newton) exerted by the Earth on the GPS satellite at this altitude.

in the definition of radiative lifetime below. what do they mean by depopulation. do they mean for 1 given energy state the amount of time until the electron gives off enough photons to be at the lowest state? or just the electron moves down 1 state? or the lifetime of a collection of mass unti all electrons in that mass have reached the ground state?

The radiative lifetime of an excited electronic state e.g. in a laser gain medium is the lifetime which would be obtained if radiative decay via the unavoidable spontaneous emission were the only mechanism for depopulating this state. It is given by the equation

A hi-tech high-powered catapult is located at point A and is aimed at an angle of = 45 ° with the horizontal.

The projectile launched from the catapult is just able to clear the peak of the mountain at the top of its

trajectory. The elevation of the catapult is 423 m above sea level and the distance d is 4031 m.

Find the following:

(a) The velocity V₀ that the projectile leaves the catapult (in m/s),

(b) The time it takes the projectile to reach the peak of its trajectory (in seconds),

(c) The maximum height above sea level, h, the projectile reaches (in metres),

(d) The time it takes for the projectile to hit the water (in seconds), and

(e) The range, R, of the projectile (in metres).

This interesting activity examines the effect of weight upon terminal velocity. Gather together some nested coffee filters. Leaving them in their original shape, measure the time it takes for one, two, three, four, and five nested filters to fall to the floor from the same height (roughly 2 m). (Note that, due to the way the filters are nested, drag is constant and only mass varies.) They obtain terminal velocity quite quickly, so find this velocity as a function of mass. Plot the terminal velocity, v versus mass. Also plot  v-squared versus mass. Which of these relationships is more linear? What can you conclude from these graphs?

- An 80 kg man stands in a very strong wind moving at 13 m/s at torso height. As you know, he will need to lean in to the wind, and we can model the situation to see why. Assume that the man has a mass of 80 kg, with a center of gravity 1.0 mabove the ground. The action of the wind on his torso, which we approximate as a cylinder 50 cmwide and 90 cm long centered 1.2 m above the ground, produces a force that tries to tip him over backward. To keep from falling over, he must lean forward.

-Part A: What is the magnitude of the torque provided by the wind force? Take the pivot point at his feet. Assume that he is standing vertically. Assume that the air is at standard temperature and pressure. Express your answer with the appropriate units.

τ =

-Part B: At what angle to the vertical must the man lean to provide a gravitational torque that is equal to this torque due to the wind force?Express your answer in degrees.

θ =

Consider a long, thin, plastic cylindrical shell centered at the origin. It has a radius 2R and a linear charge density -3 λ .

b. Use Gauss's Law to find the electric field (mag and direction) at a distance x=3R from the origin.

Now a long line of charge (parallel to the axis of the cylinder) is added at a distance x=4R with linear charge density + λ .

c. use superposition to find the force (mag. and direction) on an electron placed at x=3R

A rectangular loop has 17 turns with sides w=.03m and l=.06m. The current is 9A. What is the force on each side and the torque on the loop if the external field is 0.5 T and is directed: (a) parallel to the plane of the loop (B1) (along the positive x-axis)? (b) normal to the plane of the loop (B2) (into the paper)?

Use the exact values you enter to make later calculations. Part A A group of students performed the same "Ohm's Law" experiment that you did in class. They obtained the following results: Trial ΔV (volts) I (mA) 1 1.00 4.4 2 1.90 8.4 3 3.10 13.3 4 3.90 16.8 5 5.10 22.2 where ΔV is the voltage difference across the resistor and I is the current traveling through the resistor at the same time. (a) Analyze the data. (You will not submit this spreadsheet. However, the results will be needed later in this problem.) (i) Enter the above data into an Excel spreadsheet. (ii) Make a plot of the voltage difference vs. current. Hint (iii) Use the trendline option in Excel to fit the data of voltage difference versus current to get the slope and intercept. Hint (b) Determine the slope and y-intercept of your graph, and report these values below. (Use ohm for Ω.) slope = y-intercept = Part B Your mischievous lab partner takes the resistor that you just experimented with and assembles it in a network with one other resistor and places them inside a black box. He challenges you to tell him the configuration of the resistors inside the box. Being an industrious physics student you connect the leads of the black box to your power source, voltmeter (in parallel), and ammeter (in series) and take the following simultaneous measurements. ΔV (volts) I (mA) 4.28 11.5 Use the above measurements to find the equivalent resistance of the arrangement. (Use ohm for Ω.) Req = Based on your value of the equivalent resistance, what must the arrangement be? in series in parallel Part C Now that you've answered his challenge, your lab partner asks you to give the resistance of the resistor that he added to the one you experimented with. Using the information you obtained in parts A and B, predict this value of the resistance of the second resistor.

two particles having charges q1=0.500nC and q2 8.00nC are separated by a distance of 1.20m. at what point along the line connecting the two charges is the total electric field due to the two charges equal zero?

THIS IS ASTR 100

1. The latitude of Seattle is 47 degrees north. How many degrees above the north point of the horizon is the north celestial pole as seen from Seattle?

2. Circumpolar stars circle around the north celestial pole [clockwise, counterclockwise]

3. The Earth rotates from [west to east, east to west].

4. If you travel south, Polaris would get [higher, lower] in the sky.

5. Where on Earth could you see all the constellations rise and set?

6. Astronomers measure distances across the sky in [inches, meters, angles]

7. According to the Universe Bowl (See page 6), on the time scale civilization began about [1 yard, 1 foot, less than 1 inch] from the other goal line.

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)

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?

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.

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

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.