OC userin Physics·8 Jan 20182.5 . Starting from the front door of a ranch house, you walk 60.0 m due east to a windmill, turn around, and then slowly walk 40.0 m west to a bench, where you sit and watch the sunrise. It takes you 28.0 s to walk from the house to the windmill and then 36.0 s to walk from the windmill to the bench. For the entire trip from the front door to the bench, what are your (a) average velocity and (b) average speed?
OC userin Physics·7 Jan 20185.27 .. CP A stockroom worker pushes a box with mass 16.8 kg on a horizontal surface with a constant speed of 3.50 m/s. The coefficient of kinetic friction between the box and the surface is 0.20. (a) What horizontal force must the worker apply to maintain the motion? (b) If the force calculated in part (a) is removed, how far does the box slide before coming to rest?
OC userin Physics·8 Jan 20188.16.A 68.5-kg astronaut is doing a repair in space on the orbiting space station. She throws a 2.25-kg tool away from her at 3.20 m/s relative to the space station. With what speed and in what direction will she begin to move?
OC userin Physics·9 Jan 201831.9. (a) What is the reactance of a 3.00-H inductor at a fre- quency of 80.0 Hz? (b) What is the inductance of an inductor whose reactance is 120 12 at 80.0 Hz? (c) What is the reactance of a 4.00-F capacitor at a frequency of 80.0 Hz? (d) What is the capacitance of a capacitor whose reactance is 120 at 80.0 Hz?
OC userin Physics·6 Jan 2018Q1.1 How many correct experiments do we need to disprove a theory? How many do we need to prove a theory? Explain.
OC userin Physics·7 Jan 201814.1. BIO (a) Music. When a person sings, his or her vocal cords vibrate in a repetitive pattern that has the same frequency as the note that is sung. If someone sings the note B flat, which has a frequency of 466 Hz, how much time does it take the person's vocal cords to vibrate through one complete cycle, and what is the angular frequency of the cords? (b) Hearing. When sound waves strike the eardrum, this membrane vibrates with the same frequency as the sound. The highest pitch that young humans can hear has a period of 50.0 us. What are the frequency and angu- lar frequency of the vibrating eardrum for this sound? (c) Vision. When light having vibrations with angular frequency ranging from 2.7 X 10" rad/s to 4.7 x 101 rad/s strikes the retina of the eye, it stimulates the receptor cells there and is perceived as vis- ible light. What are the limits of the period and frequency of this light? (d) Ultrasound. High-frequency sound waves (ultrasound) are used to probe the interior of the body, much as x rays do. To detect small objects such as tumors, a frequency of around 5.0 MHz is used. What are the period and angular frequency of the molecu- lar vibrations caused by this pulse of sound?
cyancockroach621Lv1in Physics·17 Feb 2021Find the speed of a particle that takes 1.7 y longer than light to travel a distance of 4.3 ly.c
OC userin Physics·7 Jan 20189.10 .. An electric fan is turned off, and its angular velocity decreases uniformly from 500 rev/min to 200 rev/min in 4.00 S. (a) Find the angular acceleration in rev/s2 and the number of revo- lutions made by the motor in the 4.00-s interval. (b) How many more seconds are required for the fan to come to rest if the angular acceleration remains constant at the value calculated in part (a)?
OC userin Physics·7 Jan 20185.36 .. CP A 25.0-kg box of textbooks rests on a loading ramp that makes an angle a with the horizontal. The coefficient of ki- netic friction is 0.25, and the coefficient of static friction is 0.35. (a) As a is increased, find the minimum angle at which the box starts to slip. (b) At this angle, find the acceleration once the box has begun to move. (c) At this angle, how fast will the box be mov- ing after it has slid 5.0 m along the loading ramp?
OC userin Physics·5 Jan 2018Figure E14.42 14.42 . A thin metal disk with mass 2.00 X 10 kg and radius 2.20 cm is attached at its center to a long fiber (Fig. E14.42). The disk, when twisted and released, oscillates with a period of 1.00 s. Find the torsion constant of the fiber.
OC userin Physics·5 Jan 2018Q1.18 If A and B are nonzero vectors, is it possible for both Á :B and AXB to be zero? Explain.
OC userin Physics·4 Jan 20184) (10 pts) Equipment to be used in space or in airplanes is often subject to a "shake-test" to be sure it can withstand the vibrations of launch or flight. An object of mass 5.24 kg is strapped to a test platform that vibrates vertically at 120 Hz, giving rise to a maximum acceleration of 98 m/s? (10 times the acceleration of gravity, g). a. Find the maximum displacement of the platform. b. Find the maximum speed of the object during the test. c. Find the maximum net force exerted on the object.
OC userin Physics·4 Jan 20182.74 ... A flowerpot falls off a windowsill and passes the win- dow of the story below. Ignore air resistance. It takes the pot 0.380 s to pass from the top to the bottom of this window, which is 1.90 m high. How far is the top of the window below the window- sill from which the flowerpot fell?