Question: You suspend the coin from a spring

> A 200.0 µF capacitor is placed across a 12.0 V battery. When a switch is thrown, the battery is removed from the capacitor and the capacitor is connected across a heater that is immersed in 1.00 cm3 of water. Assuming that all the energy from the capacit

> What is the de Broglie wavelength of an electron with kinetic energy 7.0 TeV?

> (a) What would the net charges on the Sun and Earth have to be if the electric force instead of the gravitational force were responsible for keeping Earth in its orbit? There are many possible answers, so restrict yourself to the case where the magnitude

> Jill takes in 0.021 mol of air in a single breath. The air is taken in at 20°C and exhaled at 35°C. (a) How much heat leaves her body in a single breath due to the temperature increase of the air? Ignore the humidification of the air in the lungs and tre

> Consider two falling objects. Their masses are 3.0 kg and 4.0 kg. At time t = 0, the two are released from rest. What is the velocity of their CM at t = 10.0 s? Ignore air resistance.

> A muon decay is described by . What is the maximum kinetic energy of the electron, if the muon was at rest? Assume that the electron is extremely relativistic and ignore the small masses of the neutrinos.

> Imagine that 501 people are present in a movie theater of volume 8.00 × 103 m3 that is sealed shut so no air can escape. Each person gives off heat at an average rate of 110 W. By how much will the temperature of the air have increased during a 2.0 h mov

> A Foucault pendulum has an object with a mass of 15.0 kg hung by a thin 14.0 m wire. (a) What is the oscillation frequency of this pendulum? (b) If the pendulum has a maximum oscillation angle of 6.10°, what is the maximum speed of this pendulum? (c)

> A heating coil inside an electric kettle delivers 2.1 kW of electric power to the water in the kettle. How long will it take to raise the temperature of 0.50 kg of water from 20.0°C to 100.0°C?

> A 24 V emf is connected to terminals A and B in the following circuit. Find the current in each of the resistors.

> A 7.30 kg steel ball at 15.2°C is dropped from a height of 10.0 m into an insulated container with 4.50 L of water at 10.1°C. If no water splashes, what is the final temperature of the water and steel?

> A bit of space debris penetrates the hull of a spaceship traversing the asteroid belt and comes to rest in a container of water that was at 20.0°C before being hit. The mass of the debris is 1.0 g and the mass of the water is 1.0 kg. If the space rock tr

> Why do we not notice the effects of 1014 neutrinos passing through our bodies every second?

> A thermometer containing 0.10 g of mercury is cooled from 15.0°C to 8.5°C. How much energy left the mercury in this process?

> It is a damp, chilly day in a New England seacoast town suffering from a power failure. To warm up the cold, clammy sheets, Jen decides to fill hot water bottles to tuck between the sheets at the foot of the beds. If she wishes to heat 2.0 L of water on

> An experiment is conducted with a Joule apparatus (see Fig. 14.2). The hanging objects descend through a distance of 1.25 m each time. After 30 descents, a total of 1.00 kJ has been delivered to the water. What is the total mass of the hanging objects?

> Rank the points in order of mechanical energy, from greatest to least, taking friction and air resistance into consideration.

> A scanning electron microscope is used to look at cell structure with 10 nm resolution. A beam of electrons from a hot filament is accelerated with a voltage of 12 kV and then focused to a small spot on the specimen. (a) What is the wavelength in nanome

> A series RLC circuit has R = 500.0 Ω, L = 35.0 mH, and C = 87.0 pF. What is the impedance of the circuit at resonance? Explain.

> The water passing over Victoria Falls, located along the Zambezi River on the border of Zimbabwe and Zambia, drops about 105 m. How much internal energy is produced per kilogram as a result of the fall?

> A mass of 1.00 kg of water at temperature T is poured from a height of 0.100 km into a vessel containing water of the same temperature T, and a temperature change of 0.100°C is measured. What mass of water was in the vessel? Ignore heat flow into the ves

> It takes 880 J to raise the temperature of 350 g of lead from 0°C to 20.0°C. What is the specific heat of lead?

> What is the period of oscillation for small amplitudes?

> (a) Given two identical, ideal batteries (/ ) and two identical incandescent lightbulbs (resistance = R assumed constant), design a circuit to make both bulbs glow as brightly as possible. (b) What is the power dissipated by each bulb? (c) Design a c

> Describe the use of “color” as a quantum number for the quarks.

> What is the heat capacity of a system consisting of (a) a 0.450 kg brass cup filled with 0.050 kg of water? (b) 7.5 kg of water in a 0.75 kg aluminum bucket?

> Rank these six situations in order of the temperature increase, largest to smallest. (a) 1 kJ of heat into 400 g of steel with c = 0.45 kJ/(kg·K) (b) 2 kJ of heat into 400 g of steel (c) 2 kJ of heat into 800 g of steel (d) 1 kJ of heat into 400 g of alu

> If 125.6 kJ of heat are supplied to 5.00 × 102 g of water at 22°C, what is the final temperature of the water?

> Convert 1.00 kJ to kilowatt-hours (kWh).

> Show that 1 kilowatt-hour (kW·h) is equal to 3.6 MJ.

> In a tornado or hurricane, a roof may tear away from the house because of a difference in pressure between the air inside and the air outside. Suppose that air is blowing across the top of a 2000 ft2 roof at 150 mi/h. What is the magnitude of the force o

> A nozzle of inner radius 1.00 mm is connected to a hose of inner radius 8.00 mm. The nozzle shoots out water moving at 25.0 m/s. (a) At what speed is the water in the hose moving? (b) What is the volume flow rate? (c) What is the mass flow rate?

> A meson with charge −e composed of up and/or down quarks and/or antiquarks.

> An object of mass 2.0 kg (the “projectile”) approaches a stationary object (the “target”) at 8.0 m/s. The projectile is deflected through an angle of 90.0° and its speed after the collision is 6.0 m/s. What is the speed of the target after the collision

> If the average volume flow of blood through the aorta is 8.5 × 10−5 m3/s and the cross-sectional area of the aorta is 3.0 × 10−4 m2, what is the average speed of blood in the aorta?

> A 0.15 kg baseball is pitched with a speed of 35 m/s (78 mi/h). When the ball hits the catcher's glove, the glove moves back by 5.0 cm (2 in.) as it stops the ball. (a) What was the change in momentum of the baseball? (b) What impulse was applied to th

> A garden hose of inner radius 1.0 cm carries water at 2.0 m/s. The nozzle at the end has inner radius 0.20 cm. How fast does the water move through the nozzle?

> A stationary 0.1 g fly encounters the windshield of a 1000 kg automobile traveling at 100 km/h. (a) What is the change in momentum of the car due to the fly? (b) What is the change of momentum of the fly due to the car? (c) Approximately how many flie

> A piece of metal is released under water. The volume of the metal is 50.0 cm3 and its specific gravity is 5.0. What is its initial acceleration?

> If a car (mass 1200 kg) traveling at 28 m/s is brought to a full stop in 4.0 s after the brakes are applied, find the average frictional force exerted on the car.

> An inexperienced catcher catches a 130 km/h fastball of mass 140 g within 1 ms, whereas an experienced catcher slightly retracts his hand during the catch, extending the stopping time to 10 ms. What are the average forces imparted to the two gloved hands

> A stone used to grind wheat into flour is turned through 12 revolutions by a constant force of 20.0 N applied to the rim of a 10.0 cm radius shaft connected to the wheel. How much work is done on the stone during the 12 revolutions?

> When photons with a wavelength of 120.0 nm are incident on a metal, electrons are ejected that can be stopped with a stopping potential of 6.00 V. (a) What stopping potential is needed when the photons have a wavelength of 240.0 nm? (b) What happens wh

> (a) A piece of balsa wood with density 0.50 g/cm3 is released under water. What is its initial acceleration? (b) Repeat for a piece of maple with density 0.750 g/cm3. (c) Repeat for a ping-pong ball with an average density of 0.125 g/cm3.

> In the circuit and R = 100.0 Ω. Assume the emf is ideal. If a voltage Vx = 30.0 V is needed for a circuit, what should resistance Rx be?

> A helicopter is flying horizontally at 8.0 m/s and an altitude of 18 m when a package of emergency medical supplies is ejected horizontally backward with a speed of 12 m/s relative to the helicopter. Ignoring air resistance, what is the horizontal distan

> To contain a violent mob, the riot squad approaches with fire hoses. Suppose that the rate of flow of water through a fire hose is 24 kg/s, and the stream of water from the hose moves at 17 m/s. What force is exerted by such a stream on a person in the c

> On a kitchen scale you measure the coin’s mass to be 49.7 g. You measure the mass of a small bowl of water as 314.8 g. You tie a slender thread around the coin and suspend it completely submerged in the water but not touching the bottom. The scale readin

> A child places 12 wooden blocks together, as shown in the figure. If each block has the same mass and density, where is the CM of these blocks? Each block is a cube with sides of 1.0 inch length. The origin of the coordinate system is at the center of th

> A uniform rod of length 30.0 cm is bent into the shape of an inverted U. Each of the three sides is of length 10.0 cm. Find the location, in x- and y-coordinates, of the CM as measured from the origin.

> The average density of a fish can be found by first weighing it in air and then finding the scale reading for the fish completely immersed in water and suspended from a scale. If a fish has weight 200.0 N in air and scale reading 15.0 N in water, what is

> An intergalactic spaceship is traveling through space far from any planets or stars, where no human has gone before. The ship carries a crew of 30 people (of total mass 2.0 × 103 kg). If the speed of the spaceship is 1.0 × 105 m/s and its mass (excluding

> A pilot without special training or equipment can tolerate a horizontal acceleration of up to about 9g for a short period of time (about a minute) without losing consciousness. (a) How long would it take a supersonic jet in horizontal flight to accelera

> Nine-banded armadillos (Dasypus novemcinctus) have a typical mass density of 1200 kg/m3 and a mass of 7.0 kg (including their armor). When faced with a body of water to cross, the armadillo has two choices: to hold its breath and walk across the bottom o

> A plate of uniform thickness is shaped as shown. Where is the center of gravity? Assume the origin (0, 0) is located at the lower left corner of the plate; the upper left corner is at (0, s); and the upper right corner is at (s, s).

> A square loop of wire of side 3.0 cm carries 3.0 A of current. A uniform magnetic field of magnitude 0.67 T makes an angle of 37° with the plane of the loop. (a) What is the magnitude of the torque on the loop? (b) What is the net magnetic force on the l

> Why does a 1 kg sandbag fall with the same acceleration as a 5 kg sandbag? Explain in terms of Newton's second law and his law of gravitation.

> For a system of three particles moving along a line, an observer in a laboratory measures the following masses and velocities. What is the velocity of the CM of the system?

> A car traveling at 29 m/s runs into a bridge abutment after the driver falls asleep at the wheel. (a) If the driver is wearing a seat belt and comes to rest within a 1.0 m distance, what is his acceleration (assumed constant)? (b) A passenger who isn't

> A solid piece of plastic, with a density of 890 kg/m3, is placed in oil with a density of 830 kg/m3 and the plastic sinks (1). Then the plastic is placed in water and it floats (2). (a) What percentage of the plastic is submerged in the water? (b) Fina

> A 0.122 kg dart is fired from a gun with a speed of 132 m/s horizontally into a 5.00 kg wooden block. The block is attached to a spring with a spring constant of 8.56 N/m. The coefficient of kinetic friction between the block and the horizontal surface i

> A fish uses a swim bladder to change its density so it is equal to that of water, enabling it to remain suspended under water. If a fish has an average density of 1080 kg/m3 and mass 10.0 g with the bladder completely deflated, to what volume must the fi

> Two pendulum bobs have equal masses and lengths (5.1 m). Bob A is initially held horizontally while bob B hangs vertically at rest. Bob A is released and collides elastically with bob B. How fast is bob B moving immediately after the collision?

> A streetcar named Desire travels between two stations 0.60 km apart. Leaving the first station, it accelerates for 10.0 s at 1.0 m/s2 and then travels at a constant speed until it is near the second station, when it brakes at 2.0 m/s2 in order to stop at

> An aluminum cylinder weighs 1.03 N. When this same cylinder is completely submerged in alcohol, the volume of the displaced alcohol is 3.90 × 10−5 m3. If the cylinder is suspended from a scale while submerged in the alcohol, the scale reading is 0.730 N.

> A boy of mass 60 kg is sledding down a 70 m slope starting from rest. The slope is angled at 15° below the horizontal. After going 20 m along the slope, he passes his friend, who hops onto the sled. The friend has a mass of 50 kg, and the coefficient of

> How should the disk be oriented to prevent rocking from side to side and from bow to stern? Does this orientation make it difficult to steer the ship? Explain.

> At the surface of a freshwater lake the air pressure is 1.0 atm. At what depth under water in the lake is the water pressure 4.0 atm?

> A door weighing 300.0 N measures 2.00 m × 3.00 m and is of uniform density; that is, the mass is uniformly distributed throughout the volume. A doorknob is attached to the door as shown. Where is the center of gravity if the doorknob weighs 5.0 N and is

> A Vulcan spaceship has a mass of 65 000 kg and a Romulan spaceship is twice as massive. Both have engines that generate the same total force of 9.5 × 106 N. (a) If each spaceship fires its engine for the same amount of time, starting from rest, which wi

> If the cylinder rotates at 300.0 rev/min, what is the magnitude of the average torque required to tilt its axis by 60.0° in a time of 3.00 s? [Hint: Draw a vector diagram of the initial and final angular momenta.]

> If a feather and a lead brick are dropped simultaneously from the top of a ladder, the lead brick hits the ground first. What would happen if the experiment is repeated on the surface of the Moon?

> A baseball batter hits a long fly ball, giving it an initial velocity 45° above the horizontal. The ball rises to a maximum height of 44 m. An outfielder on the opposing team starts running at 7.6 m/s the instant the ball is hit. What is the farthest the

> At the beginning of a scene in an action movie, the 78.0 kg star, Indianapolis Jones, stands on a ledge 3.70 m above the ground and the 55.0 kg heroine, Georgia Smith, stands on the ground. Jones swings down on a rope, grabs Smith around the waist, and c

> The snow leopard (Uncia uncia) is an endangered species that lives in the mountains of central Asia. It is thought to be the longest jumper in the animal kingdom. If a snow leopard jumps at 35° above the horizontal and lands 15.0 m away on flat ground, w

> Consider the merry-go-round of Practice Problem 8.1. The child is initially standing on the ground when the merry-go-round is rotating at 0.75 rev/s. The child then hops onto the merry-go-round. How fast is the merry-go-round rotating now? By how much di

> Pendulum bob A has half the mass of pendulum bob B. Each bob is tied to a string that is 5.1 m long. When bob A is held with its string horizontal and then released, it swings down and, once bob A's string is vertical, it collides elastically with bob B.

> The rotational inertia for a diver in a pike position is about 15.5 kg·m2; it is only 8.0 kg·m2 in a tuck position. (a) If the diver gives himself an initial angular momentum of 106 kg·m2/s as he jumps off the b

> It is the bottom of the ninth inning at a baseball game. The score is tied and there is a runner on second base when the batter gets a hit. The 85 kg base runner rounds third base and is heading for home with a speed of 8.0 m/s. Just before he reaches ho

> A potentiometer is a resistor with a sliding contact. It can be used to measure emfs accurately (Problem 131) or to supply a variable voltage to a circuit (Problem 132). In the diagram with switch S1 closed and S2 open, there is no current through the ga

> A diver can change his rotational inertia by drawing his arms and legs close to his body in the tuck position. After he leaves the diving board (with some unknown angular velocity), he pulls himself into a ball as closely as possible and makes 2.00 compl

> A weightless rod, 10.0 m long, supports three weights as shown. Where is its center of gravity?

> Gerald wants to know how fast he can throw a ball, so he hangs a 2.30 kg target on a rope from a tree. He picks up a 0.50 kg ball of putty and throws it horizontally against the target. The putty sticks to the target and the putty and target swing up a v

> A spoked wheel with a radius of 40.0 cm and a mass of 2.00 kg is mounted horizontally on frictionless bearings. JiaJun puts his 0.500 kg guinea pig on the outer edge of the wheel. The guinea pig begins to run along the edge of the wheel with a speed of 2

> A radium nucleus (mass 226 u) at rest decays into a radon nucleus (symbol Rn, mass 222 u) and an alpha particle (symbol α, mass 4 u). (a) Find the ratio of the speeds vα/vRn after the decay. (b) Find the ratio of the magnitudes of the momenta pα/pRn. (

> Two otherwise identical conducting spheres carry charges of +5.0 µC and −1.0 µC. They are initially a distance L apart. The distance L is much larger than the radii of the spheres. The spheres are brought together, touched together, and then returned to

> A uniform disk with a mass of 800 g and radius 17.0 cm is rotating on frictionless bearings with an angular speed of 18.0 Hz when Jill drops a 120 g clod of clay on a point 8.00 cm from the center of the disk, where it sticks. What is the new angular spe

> A particle has a constant acceleration of 5.0 m/s2 to the east. At time t = 0, it is 2.0 m east of the origin and its velocity is 20 m/s north. What are the components of its position vector at t = 2.0 s?

> Can a body in free fall be in equilibrium? Explain.

> In Example 7.8, suppose instead that the fragment of mass 2M/3 has zero velocity immediately after the explosion. Where does the other fragment land?

> A figure skater is spinning at 10.0 rad/s with her arms extended. Her rotational inertia is 2.50 kg·m2. After pulling her arms in, her rotational inertia is 1.60 kg·m2. How much work does she do to pull her arms in while spinning?

> In each of six electric motors, a cylindrical coil with N turns and radius r is immersed in a magnetic field of magnitude B. The current in the coil is I. Rank the motors in order of the maximum torque on the coil, greatest to smallest. (a) N = 100, r =

> Two identical gliders, each with elastic bumpers and mass 0.10 kg, are on a horizontal air track. Friction is negligible. Glider 2 is stationary. Glider 1 moves toward glider 2 from the left with a speed of 0.20 m/s. They collide. After the collision, wh

> A skater is initially spinning at a rate of 10.0 rad/s with a rotational inertia of 2.50 kg·m2 when her arms are extended. What is her angular velocity after she pulls her arms in and reduces her rotational inertia to 1.60 kg·m2?

> A trap door, of length and width 1.65 m, is held open at an angle of 65.0° with respect to the floor. A rope is attached to the raised edge of the door and fastened to the wall behind the door in such a position that the rope pulls perpendicul

> A flat, circular metal disk of uniform thickness has a radius of 3.0 cm. A hole is drilled in the disk that is 1.5 cm in radius. The hole is tangent to one side of the disk. Where is the CM of the disk now that the hole has been drilled? [Hint: The origi

> Find the mass (in kg) of one molecule of CO2.

> A figure skater is spinning at a rate of 1.0 rev/s with her arms outstretched. She then draws her arms in to her chest, reducing her rotational inertia to 67% of its original value. What is her new rate of rotation?

> Plot a graph of this data for a spring resting horizontally on a table. Use your graph to find (a) the spring constant and (b) the relaxed length of the spring.

> Six flywheels have masses, thicknesses, radii, and angular speeds as given in the table. Each flywheel is a solid disk. Rank the flywheels in order of their angular momentum, smallest to largest.