Why is heat a path function and give an example?
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During the 2004 Olympic Games, a shot putter threw a shot put with a speed of 12.1 m/s at an angle of 43.7° above the horizontal. She released the shot put from a height of 2.07 m above the ground.
a) How far did the shot put travel in the horizontal direction?
b) How long was it until the shot put hit the ground?
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Due to tides mean sea level off of Newport Beach reaches a height of 1.3 meters during high
tide and 0.3 meters during low tide. Successive high tides occur every 12 hours (43,200
seconds). A buoy with mass m = 40 kg is floating in the ocean off of Newport Beach.
1) Relevant concepts/equations. (5 points.)
2) Assume we begin to measure the buoy’s displacement at High tide which occurs exactly
at 12:00 am (0 seconds). Also assume we can model the buoy’s displacement as a simple
undamped oscillation. What is the amplitude and phase angle for the buoy’s
displacement? (10 points)
3) During one half cycle of six hours (21600 seconds), the buoy’s displacement passes
through an angle of 180 degrees. From this information, what is the angular frequency ω of the buoy? (5 points)
4) Using your previous answer, what is the force constant ‘k’ acting on the buoy? (5 points)
5) What is the maximum velocity of the buoy? What is the maximum acceleration of the
buoy? (10 points)
6) What is the energy of the buoy due to tidal displacement? (5 points)
7) How much work is done during one low tide to high tide cycle? How much Power per
hour is required to accomplish this? (Assume g= 9.81m/s^2 , compare your answer to a 65W light bulb which uses 65 watts per hour.)
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answer all or do not answer
SHOW ALL WORK FOR COMPUTATIONAL PROBLEMS OR NO CREDIT (write out the equation and solution)
1. Determine the number of significant figures for the following:
A) 4778526
B) 0.075
C) 850
D) 14268.5
E) 25.8 x 105
F) 3310 x 10-1
2) Convert the following into scientific notation:
A) 0.004288
B) 4200
C) 363000000
D) 0.00000363
Please use these conversion for the following problems :
1mi = 1609 m 3.79 L = 1.00 gal 1.00 mi = 1.61 km
1 foot = 12 inches 1m/s = 2.2 mi/hr 1 inch = 2.45 cm = 25.4mm
3) Express 18 mi/h in units of meters per second. (1 mi = 1609 m)
4) Convert 775,632 seconds into days
5) Convert 42 miles into feet
6) Your car gets 22.6 mi/gal on a vacation trip in the U.S. If you were figuring your mileage in Europe, how many km/L did it get?
7) Suppose that an object travels from one point in space to another. Make a comparison between the magnitude of the displacement and the distance traveled by this object. Then write or draw out an example.
A) The displacement is either greater than or equal to the distance traveled.
B) The displacement is always equal to the distance traveled.
C) The displacement is either less than or equal to the distance traveled.
D) The displacement can be either greater than, smaller than, or equal to the distance traveled.
Example -
8) If the acceleration of an object is zero, then that object cannot be moving.
A) True
B) False
EXPLAIN
9) You are driving home on a weekend from school at 51 mi/h for 115 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 hours and 45 minutes. How far is your hometown from school?
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A bicycle starts from rest with a constant acceleration 1 m/s^2. After 5 seconds of having started its movement, the brake pin of one of its handlebars, located 5 meters from the ground, is detached. What is the horizontal distance the plug travels from when it comes off until it falls to the ground?
Note: Approximate result with only one decimal place
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If a satellite is in a sufficiently low orbit, it will encounter air drag from the earth's atmosphere. Since air drag does negative work (the force of air drag is directed opposite the motion), the mechanical energy will decrease. If E decreases (becomes more negative), the radius r of the orbit will decrease. If air drag is relatively small, the satellite can be considered to be in a circular orbit of continually decreasing radius.
a.) A satellite with mass 2140 kg is initially in a circular orbit a distance 330 km above the earth's surface. Due to air drag, the satellite's altitude decreases to 205 km . Calculate the initial orbital speed.
b.) Calculate the increase in orbital speed.
c.) Calculate the initial mechanical energy.
d.) Calculate the change in kinetic energy.
e.) Calculate the change in gravitational potential energy.
f.) Calculate the change in mechanical energy.
g.) Calculate the work done by the force of air drag.
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Two 0.25 cm radius coins are separated by a 0.1 mm thick piece of paper with dielectric constant kappa = 6.475. They form a capacitor. A 8 V battery is connected to the capacitor. How much charge is stored on each coin? The area of a circle is given by pi r^2. C
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10) Which of the following statements are correct?
A) Turning up the flame under a pan of boiling water increases the water temperature so that it boils faster.
B) Sweating is an important bodily function in which heat is extracted to regulate the body temperature.
C) On a cold day, a piece of metal feels much colder than a piece of wood due the differences in their specific heats.
D) In a fixed container holding oxygen (32u) and helium (4u) gases at the same temperature the molecules have the same average speed.
E) The heat required to condense a gaseuos substance into its liquid state is called latent heat of vaporization
F) The measure of the average kinetic energy of individual molecules is referred to as temperature.
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Why don't heat pumps work well in colder climates? Is the same true of refrigerators? Explain.
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Mercury (Hg) is a metal that melts at –39 oC, and thus is a liquid for temperatures where water is liquid.
The latent heat of melting of mercury and specific heat of liquid mercury are: 1.84 kg of solid mercury at its melting point of –39 oC is placed in thermal contact with 1.17 kg of water, initially at 20 oC, such that they are thermally isolated from everything else.
What is the final temperature of the system? Give your answer in oC to at least three digits.
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Consider a pulsar, a collapsed star of high extremely high density with mass M equal to that of the Sun (2.0E30 kg), a radius R=14000m, and a rotational period T=0.023sec. A 15500kg, man made satellite is planed to place in orbit of this start. A)Find the gravity at the surface of the Star? B)The escape velocity from the surface of the star. C) The height of the satellite? D) The orbital speed of the satellite? E) To what size the pulsar must collapse to become a black hole?
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It’s your birthday, and to celebrate you’re going to make your first bungee jump. You stand on a bridge 100 m above a raging river and attach a 30-m-long bungee cord to your harness. A bungee cord, for practical purposes, is just a long spring, and this cord has a spring constant of 40 N/m. Assume that your mass is 80 kg. After a long hesitation, you dive off the bridge. How far are you above the water when the cord reaches its maximum elongation?
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The water level in a vertical glass tube 1.00 m long can be adjusted to any position in the tube. A tuning fork vibrating at 716 Hz is held just over the open top end of the tube, to set up a standing wave of sound in the air-filled top portion of the tube. (That air-filled top portion acts as a tube with one end closed and the other end open.) take the speed of sound to be 343 m/s. a) for how many different positions of the water level will sound from the fork set up a resonance in the tube's air-filled portion? What are the b) least and c) second least water height in the tube for resonance to occur?
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Multiple choice: The presence of a black hole in a galaxy core can be inferred from (a) the total mass of the galaxy; (b) the speeds of stars near the core; (c) the color of the galaxy; (d) the distance of the galaxy from the Milky Way Galaxy; or (e) the diminished brightness of starlight in the galaxy core, relative to surrounding areas.
Multiple choice: Which one of the following statements about black holes is false? (a) Inside a black hole, matter is thought to consist primarily of iron, the endpoint of nuclear fusion in massive stars. (b) Photons escaping from the vicinity of (but not inside) a black hole lose energy, yet still, travel at the speed of light. (c) Near the event horizon of a small black hole (mass = a few solar masses), tidal forces stretch objects apart. (d) A black hole that has reached an equilibrium configuration can be described entirely by its mass, electric charge, and amount of spin (“angular momentum”). (e) A black hole has an “event horizon” from which no light can escape, according to classical (i.e., non-quantum) ideas.
Multiple choice: Which one of the following statements about black holes is true? (a) The surface of the singularity of a black hole is known as the event horizon. (b) Being more massive, a supermassive black hole has a greater gravitational pull than a stellar-mass black hole, so if you approach the event horizon of a supermassive black hole, you will be torn apart more easily than if you approach the event horizon of a stellar-mass black hole. (c) If the Sun were to become a black hole of the same mass, Earth would spiral into the black hole and be eaten. (d) The “photon sphere” is a region inside a black hole where photons orbit the center, so they cannot escape. (e) In principle, energy can be extracted from a region outside a rotating black hole.
Multiple choice: Which one of the following statements about the detection (or potential detection) of black holes is false? (a) Black holes cannot be detected because they emit no light and are therefore impossible to directly observe. (b) A binary pair of black holes was recently detected through measurements of the gravitational waves emitted when they merged to form a single black hole. (c) The presence of supermassive black holes in the centers of galaxies has been inferred from the motions of stars and gas near them. (d) Evidence for black holes can be found if material in the surrounding accretion disk goes through the event horizon and fades from view, rather than releasing energy as it hits a hard stellar surface. (e) Candidate black holes are sometimes found in binary systems that suddenly brighten at X-ray wavelengths.
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A 2·g spider is dangling at the end of a silk thread. You can make the spider bounce up and down on the thread by tapping lightly on its feet with a pencil. You discover that you can give the spider the largest amplitude on the thread by tapping exactly once every second. (a) What is the spring constant of the silk thread? N/m (b) After further experimentation, you discover that if you tap at a rate of three times every two seconds, the amplitude is 20% of its maximum value. What is the damping constant for the thread? kg/s
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