Master Physics with Fun Quizzes & Brain Teasers!

the gtpase activity of g proteins is important because the g proteins are active only when gdp is bound to them. the phosphate that is released is also an important secondary messenger. hydrolysis of the phosphoanhydride bond to form gdp and inorganic phosphate provides energy for signal transduction. the phosphate is used by downstream kinases to phosphorylate target enzymes. it provides a method by which the initial signal can be terminated.
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a) the current i due to a charge q moving in a circle with frequency fev is q fev. find the current due to the electron in the first bohr orbit. (b) the magnetic moment of a current loop is i1, where a is the arca of the loop. find the magnetic moment of the electron in the first bohr orbit in units a-m?. this magnetic moment is called a bohr magneton.
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two identical loudspeakers 2.50 m apart are emitting sound waves into a room where the speed of sound is 340 m/s . abby is standing 5.50 m in front of one of the speakers, perpendicular to the line joining the speakers, and hears a maximum in the intensity of the sound.
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Find L , the magnitude of the angular momentum of the satellite with respect to the center of the planet.Express your answer in terms of m - mass of satalite,M - mass of planet,G - 6.67*10^-11, and R- radius from center of planet to satalite.
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a cylindrical can is to be made to hold 1 liter of oil. find the dimensions (the radius and the height) that will minimize the cost of the metal to manufacture the can.
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an electron confined in a one-dimensional box is observed, at different times, to have energies of 12 ev , 27 ev , and 48 ev . part a what is the minimal length of the box? express your answer in nanometers.
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A spring with spring constant 12.8 n/m hangs from the ceiling. a ball is suspended from the spring and allowed to come to rest. it is then pulled down 4.50 cm and released. the ball makes 40.0 oscillations in 22.0 seconds.What is its the mass of the ball?Express your answer using two significant figures.m = _____ gWhat is its maximum speed?Express your answer using two significant figures.
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assuming no external forces, when a tennis ball and the earth collide, if the coefficient of restitution is equal to one then we can conclude the following:
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in a stroke treatment test, patientes were immersed in a 0.C bath until their internal temperature reached 32.C To treat a 70.0 kg patient, what is the minimum amount of ice at (0.C) that is needed in the bath so that the temperature of the ice remains at 0.C?
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the 10-lb bar is released from rest in the position shown. it falls and the end of the bar strikes the horizontal surface at p. the bar rebounds to a position relative to the horizontal. if the duration of the impact is 0.01 s, what is the magnitude of the average vertical force the horizontal surface exerted on the bar at p?
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Imagine that the motions of your palms during these rotations represent the directions of vertical air motions in highs and lows. Vertical air motion in a low is therefore _____
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A group of students is asked to determine the index of refraction of a plastic block. They have a laser pointer mounted on a protractor. The laser can be pivoted and the angle of incidence of the laser on the block can be measured. However, the laser beam is not visible inside the plastic block. Only the spots on the surface of the block where the laser enters and exits are visible.(a) The rectangle below represents the plastic block. The laser beam enters at the dot on the top of the block and exits at the dot on the bottom. On the figure, indicate all the distance measurements needed to determine the index of refraction of the block. Justify why the measurements are useful to determine the index of refraction. You may add other lines to the figure to assist in your justification.
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A set of objectives outlining the party's issue positions and priorities is a definition for which of the followingn?Select one:a. Political machineb. Party platformc. Party systemd. Party organization
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. A bowling ball rolls without slipping up an inclined plane. At the bottom of the incline, its translational speed is 5 m/s. The bowling ball can be treated as a uniform sphere of mass M, radius R, and moment of inertia I = (2/5)MR2. Assuming that the system includes only the bowling ball, determine whether (a) total mechanical energy, (b) linear momentum, and (c) angular momentum are conserved during this process, and explain why or why not in each case. (d) Apply one of these conservation principles to determine the elevation gain of the ball when it comes momentarily to rest, and explain why your result does not depend on M, R, or the angle of the incline.
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Which of the following statements regarding fluid and electrolye balance are true and - A person's greatest daily water loss is most often by A. True way of sweating. B. False Interstitial fluid is the largest water compartment and intracellular fluid is the smallest. Sulfur is needed for some proteins, and phosphorus is needed for DNA and RNA. ANP, secreted by the atria of the heart, increases the excretion of Na+ ions in urine. A A drop in blood pressure caused by severe hemorrhage will stimulate the secretion of both ADH and aldosterone. ADH, secreted by the posterior pituitary, increases the absorption of water by the small intestine. By the process of osmosis, and dependent on the electrolytes present, water enters and leaves cells. Metabolic water is constantly produced, but it is the smallest water intake volume.
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what mass of aluminum metal would absord 250 kj when it melted at its melting point? the heat of fusion for aluminum is 396.6 j/g
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give a physical reason why the curve in the graph would not reach the vertical (elost) axis even if the scientists had taken data over a broader range of temperatures.
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An escalator carries you from one level to the next in an airport terminal. The upper level is 4.4m above the lower level, and the length of the escalator is 7.3m . Assume that your mass is 63kg .Part AHow much work does the up escalator do on you when you ride it from the lower level to the upper level?Part BHow much work does the down escalator do on you when you ride it from the upper level to the lower level?
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with certain exceptions, all aircraft within 30 miles of a class b primary airport from the surface upward to 10,000 feet msl must be equipped with
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Determine the components of all forces acting on member ABCD when ? = 0. Take P = 110 lb. (Round the final answers to their nearest whole number.)The components of all forces acting on member ABCD when ? = 0, areA = lb ?Bx = lb ?By = lb ?D = lb ?C = lb ?
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plot the logarithm of the resistor voltage during charging and discharging versus time. find the slope. do these graphs give you any new information?
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A vertical spring stretches 3.9 cm when a 10g object is hung from it. The object is replaced with a block of mass 25 g that oscillates up and down in simple harmonic motion. Calculate the period of motion.
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two 8.0 lightbulbs are connected in a 12 v series circuit. at what rate does the circuit use electric energy?
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Two friend in France use a pendulum hanging form the world's highest railroad bridge to exchange messages across a river. One friend attaches a letter to the end of the pendulum and releases it so that the pendulum swings across the river to the other friend. Tha brig=dge is 130.0 m above the river. How much time is needed for the letter to make one swing across the river? Assume the river is 16.0 m wide.
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