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 comparable subject just for you Request Now On the off chance that important you may utilize the rear of the page to proceed with your answer however not the rear of the past page. The pages might be isolated as a feature of the checking procedure. 5 inquiries comprise a total paper. Each question is of equivalent worth. All inquiries will be checked. The last page contains a few constants and equation that might be valuable. You may evacuate and keep this page as a gift. Helps Permitted adding machine composing actualizes 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 occurrence the previous tosses the beverage the ‘catcher’ is at (3i †10j) m from the ‘thrower’. On the off chance 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 flexibly the mash for one day’s release of the significant paper â€Å"The Record† in Kitchener-Waterloo 2. Carnival execution A turning pulley dangling from the middle tent top permits a woman craftsman (m = 40 kg) to pivot unreservedly while her accomplice (M = 100 kg) underpins her by means of a rope over the pulley. he rope length, estimated from the pulley, holding the turning craftsman is 3. 0 m and the partner isn't quickening. [4] (a) Draw a Free Body Diagram of every entertainer and the pulley; unmistakably demonstrate 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 upset) of her insurgency? 3. Going Fishing Because of severe 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 wit h the water. B A [5] (a) What is the heading of the boater for the most brief excursion? unmistakably show this point on a proper chart) [5] (b) Find the boat’s speed comparative with the shore. [5] (c) What is the most brief time for the excursion? [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 point ! , whose coefficient of static rubbing 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 ,! also,  µ, locate the base power that you have to apply to the wedge that will make the little square simply start to climb the slant. 5. Piano Moving Doofus and Diligent are moving a piano of mass M = 300 kg utilizing the pulley framework appeared in the chart. The ro pe around the pulley holding the piano, is attached to the hub of the top pulley which thus is secured to the roof. Persevering is holding the rope at the left, suspending the piano 10 meters over the ground. [4] (a) Draw free-body charts of the piano and of every pulley. Make certain to incorporate every 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. Wellbeing 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 brew 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 excursion proceeds and the vehicle turns a corner onto a parkway, going at 90 km/hr. Abruptly Doofus sees a vehicle making a beeline for them. He freezes, bolting the brakes and veering off to the privilege onto a precarious and sloppy street recompense with a level of 35%. The vehicle slides up this almost frictionless slope and grinds to a halt at a precipice 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. Steady needs to walk the remainder of the way, yet Doofus proposes to utilize the mechanized hang-lightweight plane 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 torque is 750 Watts, figures how much mass the lightweight plane 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; however 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 Instructions to refer to Physics 122 Midterm (Fall 2010), Papers