Concept explainers
You are working in your dream job: an assistant for the special effects department of a movie studio. You have just been given this assignment: the star of a horror movie is walking down a spooky hallway when suddenly, due to some unknown and strange supernatural forces, all the pictures hanging on the wall start rotating about their upper edges until they are sticking straight out from the wall! To set up this effect, you attach the pictures to the wall with hinges along their upper end and wrap 20 turns of wire around the outside frame of the picture, as shown in Figure P28.32a. You set up a uniform magnetic field in the hallway that is directed upward and oriented at an angle of γ = 5.00° to the vertical, with its horizontal component directed perpendicularly into the wall. When you send a current of I = 10.0 A through the wire around each picture, the frame swings up perpendicular to the wall as shown in Figure P28.32b. Consider a particular picture of width ω = 40.6 cm, height h = 50.8 cm, and mass m = 0.750 kg. (a) Your supervisor asks you to determine the magnetic field magnitude that is necessary for this picture to rotate so that its face is parallel to the floor and perpendicular to the wall, as in Figure P28.32b. (b) She also asks about any dangers associated with this magnetic field.
Trending nowThis is a popular solution!
Chapter 28 Solutions
Bundle: Physics for Scientists and Engineers, Volume 2, Loose-leaf Version, 10th + WebAssign Printed Access Card for Serway/Jewett's Physics for Scientists and Engineers, 10th, Multi-Term
- 7.It shows the magnitude and direction of the force at different points in space. a.direction b.arrows c.field lines d.line 8.Arrows show the magnitude and direction of the force at different points in space. The longer the arrow, the greater the___________ a. Magnitude b. Force C. Amplitude d. Distance 9. It is represented by the spacing of the lines a.distance of the field. b.velocity of the field c.magnitude of the field d.direction of the field 10.It is one way of showing gravitational field around an object. a line b.bar c.point d.arrowarrow_forwardTwo particles of masses M1=2Kg and M2=3Kg are attached to the ends of a 2.4 meter long light (massless) rigid rod. The system is rotated at a constant angular speed of 12 rad/s (radians per second) about an axis perpendicular to the rod and passing through its center. The angular momentum of system is given by A.) L = 86.4 kg m2/s B.) L = 124 kg m2/s C.) L = -7.5 kg m2/s D.) L = 2.11 kg m2/sarrow_forwardI need help with these questions and I need an explanation Is the answer for 6: A. 0.75 m B. 0.25 m C. None are correct Is the answer for 8: A. 8.0 m/s C. 24.0 m/s E. 0 m/s F. Nonearrow_forward
- In an experiment where we will use a vertically-mounted turntable that has a hub attached at its center, which has three grooves of different radius, around which one can wind a string. A mass hanging from the free end of the string provides tension, which exerts a torque on the turntable, thus causing it to rotate What effect does the diameter of the string have on the lever arm? Explain why we can ignore this effect. Please help guide me as to what the string's diameter's effect is on the lever arm, and why this effect can be ignored.arrow_forwardIf you were to create a giant tunnel through the middle of the Earth, where would you be so that the force of attraction between you and the earth be the smallest? A) Center of the earth B) 10 miles above the surface of the Earth C) 10 miles below the surface of the Earth D) Surface of the Eartharrow_forwardA stroboscope is a light that flashes on and off at a constant rate. It can be used to illuminate a rotating object, and if the flashing rate is adjusted properly, the object can be made to appear stationary. a. What is the shortest time between flashes of light that will make a three-bladed propeller appear stationary when it is rotating with an angular speed of 16.7 rev/s? b. What is the next shortest time?arrow_forward
- I need help with these questions and I need an explanation Is the answer for 8: A. -20 m/s/s B. 3.33 m/s/s C. -6.7 m/s/s D. 20 m/s/s Is the answer for 6: A. 8 m/s B. 40 m/s C. 20 m/sarrow_forwardAn amusement park ride rotates around a fixed axis such that the angular position of a point on the ride follows the equation: θ(t) = a + bt2 – ct3 where a = 1.9 rad, b = 0.75 rad/s2 and c = 0.025 rad/s3.Randomized Variables a = 1.9 radb = 0.75 rad/s2c = 0.025 rad/s3 1) Determine an equation for the angular speed of the ride as a function of time, ω(t). Write your answer using the symbols a, b, and c, instead of their numerical values. 2)Besides at t = 0, at what time t1 is the ride stopped? Give your answer in seconds. 3) What is the magnitude of the angular displacement of the ride in radians between times t = 0 and t = t1?arrow_forwardFigure OQ10.6 shows a system of four particles joined by light, rigid rods. Assume a = band M is larger than m. About which of the coordinate axes does the system have (i)the smallest and (ii) the largest moment of inertia? (a) the x axis (b) the y axis (c) the zaxis, (d) The moment of inertia is the same small value for two axes, (e) The moment ofinertia is the same for all three axes.arrow_forward
- At 714 A.M. on June 30, 1908, a huge explosion occurred above remote central Siberia, at latitude 61 N and longitude 102 E; the fireball thus created was the brightest flash seen by anyone before nuclear weapons. The Tunguska Event, which according to one chance witness “covered an enormous part of the sky,” was probably the explosion of a stony asteroid about 140 m wide. (a) Considering only Earth’s rotation, determine how much later the asteroid would have had to arrive to put the explosion above Helsinki at longitude 25 E. This would have obliterated the city. (b) If the asteroid had, instead, been a metallic asteroid, it could have reached Earth’s surface. How much later would such an asteroid have had to arrive to put the impact in the Atlantic Ocean at longitude 20 W? (The resulting tsunamis would have wiped out coastal civilization on both sides of the Atlantic.)arrow_forwardA sphere of copper has a radius of 50.0 cm and a mass of 4690 kg. A sphere of unknown metal has a radius of 30.0 cm. The surfaces of the spheres are 20.0 cm apart. The force of gravitational attraction between the two spheres is 0.372 mN. What is the mass of the unknown metal?arrow_forwardIn a hydrogen atom an electron is orbiting a proton. There are two forces between the electron and the proton. The Gravitational Force FG and the electrostatic Force FE. What is the factor FEFG of those two forces. Use the following constants to calculate the problem: me=9.1*10-31 kg mp=1.67*10-27 kg e=1.6*10-19 C k=8.99*109 Nm2/C2 r=1.01*10-10 m G=6.67⋅10−11Nm2kg2 Please give your answer FE/FG in FE/FG*1040 ie. for 6.734*1042 please write 673.4arrow_forward
- Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning