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Question: A model sailboat is slowly sailing west


A model sailboat is slowly sailing west across a pond at 0.33 m/s. A gust of wind gives the sailboat a constant acceleration of 0.30 m/s2 directed 28° south of west during a time interval of 2.0 s.
(a) If the net force on the sailboat during the 2.0 s interval has magnitude 0.375 N, what is the sailboat’s mass?
(b) What is the new velocity of the boat after the 2.0 s gust of wind?


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> A grating with 5550 slits/cm has red light of 0.680 µm incident on it. The light shines through the grating onto a screen that is 5.50 m away. (a) What is the distance between adjacent slits on the grating? (b) How far from the central bright spot is th

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> Repeat Problem 8 using the component (algebraic) method.

> Vector / has magnitude 7.1 and direction 14° below the +x-axis. Vector/ has x-component Cx = −1.8 and y-component Cy = −6.7. Compute: (a) the x- and y-components of /; (b) the magnitude and direction of / ; (c) the magnitude and direction of / ; (d

> A helicopter of mass M is lowering a truck of mass m onto the deck of a ship. (a) At first, the helicopter and the truck move downward together (the length of the cable doesn’t change). If their downward speed is decreasing at a rate of 0.10g, what is t

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> In the Bohr model of the hydrogen atom, an electron moves in a circular orbit around a stationary proton. In its lowest-energy state (the ground state), the orbital radius is 0.0529 nm. (a) What are the electric forces on the electron and on the proton?

> A copper wire of length 3.0 m is observed to stretch by 2.1 mm when a weight of 120 N is hung from one end. (a) What is the diameter of the wire and what is the tensile stress in the wire? (b) If the tensile strength of copper is 400 MPa, what is the m

> The graph shows the tension in a rubber band as it is first stretched and then allowed to contract. As you stretch a rubber band, the tension at a particular length (on the way to a maximum stretch) is larger than the tension at that same length as you l

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> A 0.50 kg block, starting at rest, slides down a 30.0° incline with static and kinetic friction coefficients of 0.35 and 0.25, respectively (see the figure with Problem 75). After sliding 85 cm along the incline, the block slides across a frictionless ho

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> A spaceship of mass m is traveling away from Earth at speed v. Its momentum has magnitude 2.5mv. (a) Find v. (b) An astronaut on the spaceship has a watch that ticks once every second. How often does the watch tick as measured by an Earth observer?

> In a simple model, the electron in a hydrogen atom orbits the proton at a radius of 53 pm and at a constant speed of 2.2 × 106 m/s. The orbital motion of the electron gives it an orbital magnetic dipole moment. (a) What is the current I in this current

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> An object with a charge of 0.890 µC is placed at the center of a cube. What is the electric flux through one surface of the cube?

> Luke is trying to catch a pesky animal that keeps eating vegetables from his garden. He is building a trap and needs to use a spring to close the door to his trap. He has a spring in his garage, and he wants to determine the spring constant of the spring

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> Some feathers of the ruby-throated hummingbird have an iridescent green color due to interference. A simplified model of the step structure of the feather is shown in the figure. If the strongest reflection for normal incidence is at λ = 520

> What fundamental particles make up an atom?

> The power supply for a pacemaker is a small amount of radioactive 238Pu. This nuclide decays by alpha decay with a half-life of 87.7 yr. The pacemaker is typically replaced every 10.0 yr. (a) By what percentage does the activity of the 238Pu source decr

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> A jogger runs counterclockwise around a path of radius 90.0 m at constant speed. He makes 1.00 revolution in 188.4 s. At t = 0, he is heading due east. (a) What is the jogger’s instantaneous velocity at t = 376.8 s? (b) What is his instantaneous veloci

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> How far along the incline does the object travel before coming to rest and then sliding back down?

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> Consider a 60.0 W incandescent lightbulb and a 100.0 W incandescent lightbulb designed for use in a household lamp socket at 120 V. (a) What are the resistances of these two bulbs? (b) If they are wired together in a series circuit, which bulb shines b

> The bottom of a thundercloud is at a potential of −1.00 × 108 V with respect to Earth's surface. If a charge of −25.0 C is transferred to Earth during a lightning strike, find the electric potential energy released. (Assume that the system acts like a ca

> Beatrice needs to drag her suitcase again (see Example 3.8). This time she pulls with a force of 105 N at 38.0° with the horizontal. The coefficients of static and kinetic friction between the suitcase and the floor are 0.273 and 0.117, respectively. (a

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> The electric potential at a distance of 20.0 cm from a point charge is +1.0 kV (assuming V = 0 at infinity). (a) Is the point charge positive or negative? (b) At what distance is the potential +2.0 kV?

> What is the speed of the object when it has moved 0.10 m along the incline?

> Find the magnetic field at the center of the square.

> Near Earth's surface the air contains both negative and positive ions due to radioactivity in the soil and cosmic rays from space. As a simplified model, assume there are 600.0 singly charged positive ions per cubic centimeter and 500.0 singly charged ne

> In an adventure movie, a 62.5 kg stunt woman falls 8.10 m and lands in a huge air bag. Her speed just before she hits the air bag is 10.5 m/s. (a) What is the total work done on the stunt woman during the fall? (b) How much work is done by gravity on t

> What does it mean if the power factor is 1? What does it mean if it is zero?

> A spring gun (k = 28 N/m) is used to shoot a 56 g ball horizontally. Initially the spring is compressed by 18 cm. The ball loses contact with the spring and leaves the gun when the spring is still compressed by 12 cm. What is the speed of the ball when i

> A 6.0 kg block, starting from rest, slides down a frictionless incline of length 2.0 m. When it arrives at the bottom of the incline, its speed is vf. At what distance from the top of the incline is the speed of the block 0.50vf?

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> A sigma baryon at rest decays into a lambda baryon and a photon: Σ0 → Λ0 + γ. The rest energies of Σ0 and Λ0 are 1192 MeV and 1116 MeV, respectively. What is the photon wavelength?

> One way to loosen the lid on a glass jar is to run it under hot water. How does that work?

> A car moving at 30 mi/h is stopped by jamming on the brakes and locking the wheels. The car skids 50 ft before coming to rest. How far would the car skid if it were initially moving at 60 mi/h? [Hint: You will not have to do any unit conversions if you s

> A hang glider moving at speed 9.5 m/s dives to an altitude 8.2 m lower. Ignoring drag, how fast is it then moving?

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> A point source of light is in front of a plane mirror. (a) Show that all the reflected rays, when extended back behind the mirror, intersect in a single point. [Hint: See Fig. 23.27a and use similar triangles.] (b) Show that the image point lies on a l

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