Vector Diagram - Higher Physics - Past Paper, Exercises of Physics

Download Vector Diagram - Higher Physics - Past Paper and more Exercises Physics in PDF only on Docsity! THE UNIVERSITY OF NEW SOUTH WALES SCHOOL OF PHYSICS PHYS1131 HIGHER PHYSICS 1A TEST 1 SESSION 1, 2000 Time Allowed: 1.5 hours INSTRUCTIONS 1. Do not read or write on this paper until instructed to do so. 2. For each test attempted, answer all questions. 3. Answer questions in the spaces provided. 4. Questions are not necessarily of equal value. 34 For each question, full working and explanation must be shown. 6. Answers must be written in ink. Pencil may only be used for drawings, sketching or graphs. 7. Portable, batter powered electronic calculators will be supplied. 8. This booklet must be handed in at the end of the examination. Family Name Initials Print Student ID Signature Question Mark 1 2 Alpulp TOTAL -4- QUESTION 1 [Marks 14] All streets in a suburb run north-south or east-west. A person wants to drive from point A to point B which is a direct distance of 15 km in direction 75° east of north. The legal speed limit is 60 km/h. {a) {b) (i) Draw a vector diagram showing the displacement vectors along streets which would take the person frum A to B. (ii) Determine the minimum time in which a person can legally drive from A to B. A car is driven due north at a constant speed of 33 m s-1 relative to the ground. Rain is falling. The rain is driven towards the north by a wind that is blowing due north. A person standing on the road sees the path of the rain drops making an angle of 22° to the vertical. The rain drops appear to the driver of the car to he falling vertically. (i) Draw a vector diagram showing the relation between the velocities of the car and the rain relative to the ground and the velocity of the rain relative to the.car. {i) | Determine the velocity of the raindrops relative to the ground. = 10+ QUESTION 4 [Marks 16] (a) Two discs are mounted on the same frictionless axis. They can rotate independently but they can alsa be brought together so that they rotate together as a single unit. Disc A has a moment of inertia of 74 = 2.5 kg m-2. Disc B has a moment of inertia of fg=5.0kgm*?, Initially Dise A is rotating at 900m rad s-! and disc B is rotating at 1800x rad s—| in the opposite direction. (i) If the two discs are coupled together, determine their angular speed afterwards. (ii) | What fraction of the initial rotational kinetic energy is lost when the two discs couple. A solid cylinder of radius r = 0.05 m and mass m = 0.9 kg starts from rest and rolls without slipping a distance of 5m as shown down a plane that is C ) inclined at 30° to the horizontal. am , The moment of inertia of a uniform cylinder of mass M and radius Ris 2 MR’. 2 () Determine the final total kinetic energy of the cylinder. (ii) Determine its final wranslationa! kinetic energy. {iii) Determine its final rotational kinetic energy. -12- QUESTION 5 [Marks 12] A 60 kg person places a 4.0 m ladder of mass 12 kg against a smooth vertical wall with the foot of the ladder 1.5 m from the wall. He/she climbs 3.0 m along the ladder. The ladder does not move. {a} Draw a sketch identifying all the forces acting on the ladder (b) Determine the force (direction and magnitude} exerted by the wall on the ladder. ic} Determine the force (direclion and magnitude} exerted by the ground on the ladder. (d) Determine the minimum value of the static coefficient of friction u, between the ground and the laddor. ~14- QUESTION 6 (Marks 11] (a) Calculate the height above the earth's surface at which the acceleration cue to the earth's gravity is g = 7.4 ms. (b) Mancen= 7-3 6x10" kg au to moon =3-82X1 Om Moye =1.99x1 0 kg ern 95in=1.SOXTO"'m Mw =5.98x10 kg Ata certain moment the sun and the monn are aligned with the earth as shown. Distances between the bodies (c) and the masses (M) are given on the diagram, which is not to scale. () Sketch a vector diagram showing the directions of the gravitational forces acting on the earth due to the moon and due to the sun, (ii) Determine the magnitude and direction of the total gravitational force acting on the earth due to the sun and the moon.