Master Physics with Fun Quizzes & Brain Teasers!

How much work is done (by a battery, generator, or some other source of potential difference) in moving Avogadro's number of electrons from an initial point where the electric potential is 9.20 V to a point where the electric potential is -6.90 V
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A mass of 5kg starts from rest and pulls down vertically on a string wound around a disk-shaped, massive pulley. The mass of the disk is 5kg and its radius is 2 m. What is the linear speed, in m/s, after the mass drops by 0.3 m
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American eels (Anguilla rostrata) are freshwater fish with long, slender bodies that we can treat as uniform cylinders 1.0 m long and 10 cm in diameter. An eel compensates for its small jaw and teeth by holding onto prey with its mouth and then rapidly spinning its body around its long axis to tear off a piece of flesh. Eels have been recorded to spin at up to 14 revolutions per second when feeding in this way. Although this feeding method is costly in terms of energy, it allows the eel to feed on larger prey than it otherwise could. The eel has a certain amount of rotational kinetic energy when spinning at 14 spins per second. If it swam in a straight line instead, about how fast would the eel have to swim to have the same amount of kinetic energy as when it is spinning? (a) 0.5 m/s; (b) 0.7 m/s; (c) 3 m/s; (d) 5 m/s.
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Calculate the force exerted by a machine that does 4800 J of work over a distance of 22.5 m?
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An energy input of 33.44kJ is required to raise the temperature of 100 grams of water from room temperature (20C) to boiling temperature (100C). How many photons of energy are needed to bring 250 grams of room temperature water to boiling if 288 mili-meter electro-magnetic radiation is used to heat the water?
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The resolving power of a microscope is proportional to the wavelength used. A resolution of 1.0 10-11 m (0.010 nm) would be required in order to "see" an atom. (a) If electrons were used (electron microscope), what minimum kinetic energy would be required for the electrons
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In 1898, the world land speed record was set by Gaston Chasseloup-Laubat driving a car named Jeantaud. His speed was 39.24 mph (63.15 km/h), much lower than the limit on our interstate highways today. Repeat the calculations of Example 2.7 (assume the car accelerates for 6 miles to get up to speed, is then timed for a one-mile distance, and accelerates for another 6 miles to come to a stop) for the Jeantaud car. (Assume the car moves in the +x direction.)Find the acceleration for the first 6 miles.
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To calculate the density of an object, which of the following values do youneed to know?A. VolumeB. BuoyancyC. WeightD. Mass
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A speeding truck travels in the positive x direction. It hits a car traveling in the positive y direction. The vehicles are deformed and travel together at anangle with the positive x-axis. What can you say about the kinetic energy of the system after the collision?Kinetic energy of the system is conserved.B.Kinetic energy of the system is partially used up in the deformation of the vehiclesKinetic energy of the system is unrelated to the deformation of the vehicles.C.D.Kinetic energy of the system is completely transformed to heat energy
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A cylinder with a moving piston expands from an initial volume of 0.150 L against an external pressure of 1.50 atm . The expansion does 217 J of work on the surroundings. What is the final volume of the cylinder
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A 4 cm diameter "bobber" with a mass of 3 grams floats on a pond. A thin, light fishing line is tied to the bottom of the bobber, and from the bottom hangs a 10 gram lead weight. The density of lead is 11.3 g/cm3. What fraction of the bobber's volume is submerged, as a percent of the total volume
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Which of the following has the lowest density?A. Mineral waterB. AirC. WaterD. Salt water
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A new ski area has opened that emphasizes the extreme nature of the skiing possible on its slopes. Suppose an ad intones "Free-fall skydiving is the greatest rush you can experience . . . but well take you as close as you can get on land. When you tip your skis down the slope of our steepest runs, you can accelerate at up to 75% of the acceleration youd experience in free fall." What angle slope could give such an acceleration?
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During a brake test, the rear-engine car is stopped from an initial speed of 86 km/h in a distance of 47 m. If it is known that all four wheels contribute equally to the braking force, determine the braking force F at each wheel. Assume a constant deceleration for the 1210-kg car.
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In 1949, an automobile manufacturing company introduced a sports car (the "Model A") which could accelerate from 0 to speed v in a time interval of t. In order to boost sales, a year later they introduced a more powerful engine (the "Model B") which could accelerate the car from 0 to speed 2.92v in the same time interval. Introducing the new engine did not change the mass of the car. Compare the power of the two cars, if we assume all the energy coming from the engine appears as kinetic energy of the car.
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That 85 kg paratrooper from the 50's was moving at constant speed of 56 m/s because the air was applying a frictional drag force to him that matched his weight. If he fell this way for 40 m, how much heat was generated by this frictional drag force in J
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A 4.0 g string, 0.36 m long, is under tension. The string produces a 500 Hz tone when it vibrates in the third harmonic. The speed of sound in air is 344 m/s. In this situation, the wavelength of the standing wave in the string, in SI units, is closest to:
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A disk of mass m and moment of inertia of I is spinning freely at 6.00 rad/s when a second identical disk, initially not spinning, is dropped onto it so that their axes coincide. In a short time, the two disks are corotating. What is the angular speed of the new system
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A Ferris wheel turns at a constant 150.0 revolutions per hour. (a) Express this rate of rotation in units of radians per second. 36.44 Incorrect: Your answer is incorrect. Write the given rate of rotation with its given units, then convert the units to the desired units. rad/s (b) If the wheel has a radius of 13.0 m, what arc length does a passenger trace out during a ride lasting 4.95 min
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Web Spiders and Oscillations All spiders have special organs that make them exquisitely sensitive to vibrations. Web spiders detect vibrations of their web to determine what has landed in their web, and where. In fact, spiders carefully adjust the tension of strands to "tune" their web. Suppose an insect lands and is trapped in a web. The silk of the web serves as the spring in a spring-mass system while the body of the insect is the mass. The frequency of oscillation depends on the restoring force of the web and the mass of the insect. Spiders respond more quickly to larger - and therefore more valuable - prey, which they can distinguish by the web's oscillation frequency. Suppose a 14 mg fly lands in the center of a horizontal spider's web, causing the web to sag by 4.0 mm. Assuming that the web acts like a spring, what is the spring constant of the web? Which of the following is it?a. 0.027N/mb. 27N/mc. 2.7N/md. 0.27N/mModeling the motion of the fly on the web as a mass on a spring, at what frequency will the web vibrate when the fly hits it? Which of the following is it?a. 25Hzb. 7.9Hzc. 0.79Hzd. 2.5Hz
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Two astronauts, of masses 60 kg and 80 kg, are initially right next to each other and at rest in outer space. They suddenly push each other apart. What is their separation after the heavier astronaut has moved 12m
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Find the total kinetic energy Ktot of a dumbbell of mass m when it is rotating with angular speed and its center of mass is moving translationally with speed v. Denote the dumbbell's moment of inertia about its center of mass by Icm. Note: If you approximate the spheres as point masses of mass m/2 each located a distance r from the center and ignore the moment of inertia of the connecting rod, then the moment of inertia of the dumbbell is given by Icm=mr^2, but this fact will not be necessary for this problem.Required:Find the total kinetic energy Ktot of the dumbell.
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Electric charge can accumulate on an airplane in flight. You mayhave observed needle-shaped metal extensions on the wing tips andtail of an airplane. Their purpose is to allow charge to leak offbefore much of it accumulates. The electric field around the needleis much larger than the field around the body of the airplane and,can become large enough to produce dielectric breakdown of the air,discharging the airplane. To model this process, assume that twocharged spherical conductors are connected by a long conductingwire and a charge of 22.0 C isplaced on the combination. One sphere, representing the body of theairplane, has a radius of 6.00 cm, and the other, representing thetip of the needle, has a radius of 2.00 cm.(a) What is the electric potential of eachsphere?(b) What is the electric field at the surface of each sphere?
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High blood pressure is a physical response to stress.Please select the best answer from the choices provided. True Or false
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