Physics 122 Midterm (Fall 2010) Free Essays

College of Waterloo Department of Physics Astronomy Physics 121 †Midterm Fall 2010 Instructors: Dr. Robert Mann (areas 2,3) Dr. Guenter Scholz (segment 1) Date: November 4 , 2009 Time: 19:00-21:00 Duration: 2 hours (120 minutes) rh Instructions Important: Write your name and understudy ID on each page. We will compose a custom exposition test on Material science 122 Midterm (Fall 2010) or then again any comparative theme just for you Request Now In the event that vital you may utilize the rear of the page to proceed with your answer yet not the rear of the past page. The pages might be isolated as a major aspect of the checking procedure. 5 inquiries establish a total paper. Each question is of equivalent worth. All inquiries will be tallied. The last page contains a few constants and recipe that might be valuable. You may expel and keep this page as a trinket. Helps Permitted mini-computer composing executes Question Points Score 1 2 3 4 5 6 Total: 20 1. an Up, up, and away [15] A balloonist can’t oppose tossing a beverage to another balloonist. The ‘thrower’ is moving at v = - 15j m/min while the ‘catcher’ is moving at v = 15j m/min. At the case the previous tosses the beverage the ‘catcher’ is at (3i †10j) m from the ‘thrower’. In the event that the toss is level, at what speed does the beverage should be tossed to be gotten? 1. Logging [10] Estimate, by means of a sensible count, the quantity of trees that should be chopped down to gracefully the mash for one day’s version of the significant paper â€Å"The Record† in Kitchener-Waterloo 2. Bazaar execution A turning pulley dangling from the inside tent top permits a woman craftsman (m = 40 kg) to pivot openly while her accomplice (M = 100 kg) bolsters her by means of a rope over the pulley. he rope length, estimated from the pulley, holding the pivoting craftsman is 3. 0 m and the aide isn't quickening. [4] (a) Draw a Free Body Diagram of every entertainer and the pulley; unmistakably show the powers. 5] (b) What is the pressure in the rope? [5] (c) At what edge, concerning the vertical, is the lady’s supporting rope? [6] (d) What is the period (time for one insurgency) of her upset? 3. Going Fishing Because of harsh climate, a boater needs to go as fast as conceivable over a channel from a fishing spot at ‘A’ to the harbor at ‘B’. The harbor is 10. 0 km East and 15 km North of his fishing spot. A tide is streaming at 3. 0 km/hr 45 toward the South of East, and the boat’s speed is 8. 00 km/hr comparative with the water. B A [5] (a) What is the heading of the boater for the most limited outing? plainly show this edge on a fitting graph) [5] (b) Find the boat’s speed comparative with the shore. [5] (c) What is the most limited time for the outing? [5] (d) If there were no tide, what amount time would the excursion require? m F 4. Obstructed ! A little square of mass m lays on the slope of a wedge of mass M and edge ! , whose coefficient of static contact is  µ. The wedge is on a frictionless surface. [8] (an) If m = 1 kg and M = 20 kg, what is the base power, F, you have to apply to the wedge that will keep the little square from sliding down the slant if  µ =0 and ! 45 o ? [12] (b) For general estimations of m, M ,! furthermore,  µ, locate the base power that you have to apply to the wedge that will make the little square simply start to climb the incline. 5. Piano Moving Doofus and Diligent are moving a piano of mass M = 300 kg utilizing the pulley framework appeared in the graph. The r ope around the pulley holding the piano, is attached to the hub of the top pulley which thusly is secured to the roof. Tireless is holding the rope at the left, suspending the piano 10 meters over the ground. [4] (a) Draw free-body graphs of the piano and of every pulley. Make certain to incorporate every single pertinent power. [7] (b) How much power is Diligent applying to keep the piano suspended? [6] (c) Doofus attempts to help Diligent by climbing onto the upper stage and removing the rope from the snare connecting the highest pulley to the stage, figuring he can help pull from that point. What amount power must he apply to keep the piano suspended? [3] (d) Doofus finds that he can't bolster the weight and relinquishes the rope. To what extent does Diligent need to avoid the piano before it hits the ground? 6. Security First Doofus and Diligent are setting off to a gathering. They each lock themselves in with safety belts Diligent is hold a 25 kg barrel of lager on his lap while Doofus drives. [4] (a) While voyaging 60 km/hr, Doofus needs to make a crisis stop over a separation of 45 m. What amount power will Diligent’s arms need to apply on the barrel during this deceleration period with the goal that it remains on his lap? [4] (b) The outing proceeds and the vehicle turns a corner onto a parkway, going at 90 km/hr. Out of nowhere Doofus sees a vehicle making a beeline for them. He freezes, bolting the brakes and veering off to the privilege onto a lofty and sloppy street stipend with a level of 35%. The vehicle slides up this almost frictionless slope and grinds to a halt at a bluff edge. What amount separation does it spread? [7] (c) From the highest point of this precipice they can see the area of the gathering a 2 kilometers east and 1000 meters above where they are. Tenacious needs to walk the remainder of the way, however Doofus proposes to utilize the mechanized hang-lightweight flyer in the rear of the vehicle to fly over yonder with the barrel. He says he can fly straight there with a speed of 40 km/hr utilizing its 6 drive engine, and sets off with the barrel. While he is preparing, Diligent, realizing that a strength is 750 Watts, figures how much mass the lightweight flyer can convey. He takes a gander at the bundle and sees that air lightness alone can generally bolster the lightweight flyer as long as it isn't conveying anything; yet Doofus weighs 75 kg. Would doofus be able to convey the barrel along these lines? [5] (d) As Doofus takes off, Diligent yells out how moderate he should travel to get to the gathering. What does he yell?. Valuable Formulae Kinematics (a=const) Work, WKE, Power ! ! ! 1! r2 = r1 + v1 (t2 ! t1 ) + a (t2 ! t1 ) 2 ! ! ! v2 = v1 + a (t 2 ! t1 ) ! ! W = F † ! = Fx ! x + Fy ! y + Fz ! z (consistent power) ! ! ! 2 v2 ! v12 = 2a † (r2 ! r1 ) Circular Motion K= 1 2 mv 2 Kinetic vitality Wnet = K f † K I = ! K ar = air conditioning = v2 r at = dv dt (uniform movement) P= !W ! t ! ! dr ! ! dW =F! = F ! v dt T U = 2! r dist = speed v Newton’s Laws ! F net = ! F = mama ! ! F12 = ! F21 ! ! Fg = mg Math ! ! ? A + B = ( Ax + Bx )I + ( Ay + B y ) ? j ! ! A ! B = Ax Bx + Ay B y Fs (x) = ! kx sin 2 ! + cos 2 ! = 1 f s ! f s ,max =  µ s n f k =â µ k n Relative Motion sin A wrongdoing B sin C = a b c a 2 = b 2 + c 2 ! 2bc cos A ! ! ! v AB = v A ! vB The most effective method to refer to Physics 122 Midterm (Fall 2010), Papers