You have two lenses at your disposal, one with a focal length f1=35.0 cm , the other with a focal length f2=-35.0cm .Which of these two lenses would you use to project an image of a lightbulb onto a wall that is far away?If you want to produce an image of the bulb that is enlarged by a factor of 2.50, how far from the wall should the lens be placed?
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Physics is the study of matter, motion, energy and force. It is a fundamental science that seeks to understand and explain the universe around us and beyond.
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The tub of a washer goes into its spin-dry cycle, starting fromrest and reaching an angular speed of 5.0 rev/s in 7.0 s. At thispoint, the person doing the laundry opens the lid, and a safetyswitch turns off the washer. The tub slows to rest in 12.0 s.Through how many revolutions does the tub turn during this 19 sinterval? Assume constant angular acceleration while it is startingand stopping.
I am stuck on this question, with an idea of what the answerif:
An engineer has designed a small and precise device with a built inmass on a spring damped oscillator with a spring constant k = 10.0N/M, mass m 1.00 g and variable damping constant b. The first testof the device showed that the amplitude of oscillations dropped to25% of its initial value in 23.1 ms. This time interval wasinappropriately long for the project and should be shortened. Canthe engineer halve the initially obtained time it takes to reducethe apmplitude to 25% of its initial value by varying the dampingconstant in his device?
a) if yes, what change in the damping constant b can help theengineer reach the design objective?
b) if no, why not?
I think that I am going to run into an issue of over damping,meaning that the answer is b. Either way, I have tried to solve forb itself, and to no avail. Any help would be greatlyappreciated.
Two railroad freight cars with masses 130 and 140 approach withequal speeds of 0.320. They collide, the lighter car reboundingopposite its original direction at 0.300.
Part A: Find the velocity of the heavier car after the collision.Assume the original direction of the lighter car is positive.
The velocity is 0.26 m/s
Part B: What fraction of the original kinetic energy was lost inthis inelastic collision?
A smooth circular hoop with a radius of 0.900 m is placed flat onthe floor. A 0.350-kg particle slides around the inside edge of thehoop. The particle is given an initial speed of 7.50 m/s. After onerevolution, its speed has dropped to 5.00 m/s because of frictionwith the floor.
(a) Find the energy transformed from mechanical to internal in theparticleâhoopâfloor system as a result of friction in onerevolution.
(b) What is the total number of revolutions the particle makesbefore stopping? Assume the friction force remains constant duringthe entire motion.
A bullet of mass 11.7 g is fired into an initially stationary blockand comes to rest in the block. The block, of mass 1.07 kg, issubject to no horizontal external forces during the collision withthe bullet. After the collision, the block is observed to move at aspeed of 4.90 m/s.
How much kinetic energy is lost?
The parking brake on a 2000 kg Cadillac has failed, and it is rolling slowly, at 4.00 mph, toward a group of small children. Seeing the situation, you realize you have just enough time to drive your 2000 kg Volkswagen head-on into the Cadillac and save the children. With what speed should you impact the Cadillac to bring it to a halt?
In a large centrifuge used for training pilots and astronauts, a small chamber is fixed at the end of a rigid arm that rotates in a horizontal circle. A trainee riding in the chamber of a centrifuge rotating with a constant angular speed of 2.2 rad/s experiences a centripetal acceleration of 2.9 times the acceleration due to gravity. In a second training exercise, the centrifuge speeds up from rest with a constant angular acceleration. When the centrifuge reaches an angular speed of 2.2 rad/s, the trainee experiences a total acceleration equal to 4.7 times the acceleration due to gravity. (a) How long is the arm of the centrifuge? (b) What is the angular acceleration in the second training exercise?
A rectangular loop of wire with side .2 and .35 m lies in a plance perpendicular to a constant magnetic field. The magnetic field has a magnitude of .65T and is directed parallel to the normal of the loop's surface. In a time of .18sec. one-half of the loop is them folded back onto the other half . Determine the magnitude of the average emf induced in the loop.
Figure 9-48 gives an overhead view of the path taken by a cue ball with mass m as it bounces from a rail of a pool table. The ball's initial speed is vi and the angle of impact is ?1. The bounce reverses the y component of the ball's velocity but does not alter the x component. What are (a) angle ?2 and (b) the change in the ball's linear momentum in unit-vector notation? (The fact that the ball rolls is irrelevant to the problem.) State your answers in terms of the given variables.
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