COLLEGE OF FOUNDATION AND GENERAL STUDIES PUTRAJAYA CAMPUS FINAL EXAMINATION TRIMESTER I 2012/2013

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COLLEGE OF FOUNDATION AND GENERAL STUDIES PUTRAJAYA CAMPUS FINAL EXAMINATION TRIMESTER I 2012/2013 PROGRAMME SUBJECT CODE SUBJECT : Foundation in Engineering : PHYF115 : Physics I DATE : September

1 COLLEGE OF FOUNDATION AND GENERAL STUDIES PUTRAJAYA CAMPUS FINAL EXAMINATION TRIMESTER I 2012/2013 PROGRAMME SUBJECT CODE SUBJECT : Foundation in Engineering : PHYF115 : Physics I DATE : September 2012 TIME VENUE : 2 ½ hours : Library Exam Hall INSTRUCTIONS TO CANDIDATES: 1. This paper consists of TEN (10) questions in Part A and FIVE (5) questions in Part B in FIVE (5) pages. 2. Answer ALL questions in Part A and ANY FOUR(4) questions in Part B. 3. Write ALL answers in the answer booklet provided. 4. Write answer to each question in Part B on a new page. THIS QUESTION PAPER CONSISTS OF 6 PRINTED PAGES INCLUDING THIS COVER PAGE. Page 1 of 6

2 Part A: (Answer ALL questions - each question is worth 2 marks) Constants: g = 9.80 ms -2, G = 6.67 x N.m 2 kg An ore loader moves 1.6 x 10 3 tons/h from a mine to the surface. Convert this rate to lb /s. (1 ton = 2 x 10 3 lb) 2. A particle moves according to the equation x =10t 2, where x is in meters and t is in second. Find the average velocity from 2.00 s to 2.50 s. 3. One point in a plane has polar coordinates (2.50 m, 30.0 o ). Determine the Cartesian coordinate of this point. 4. A 2.00-kg crate is placed on a friction inclined plane of angle θ = 30 o as shown in Figure 1. Draw all forces acting on the box in x- and y- axis. Determine the acceleration, a of the crate after it is released if the friction coefficient is zero. y x Figure 1 5. A 500-g object is swung in a vertical circular path on a string 1.00 m long. If its speed is 4.00 ms -1 at the top of the circle, what is the tension in the string there? 6. A 700-kg elevator starts from rest. It moves upward for 3.00 s with constant acceleration until it reaches its cruising speed of 2.00 ms -1. What is the average power of the elevator motor during this period? Page 2 of 6

3 7. A 4.0-kg ball with an initial velocity of (5 + 3 ) m/s collides with a wall and rebounds with a velocity of ( ) m/s. What is the impulse exerted on the ball by the wall? 8. The turntable of a record player has an angular velocity of 8.00 rads -1 when it is turned off. The turntable comes to rest 2.50 s after being turned off. Through how many radians does the turntable rotate after being turned off? Assume constant angular acceleration. 9. A particle whose mass is 3.00 kg moves in the xy plane with a constant speed of 3.50 ms -1 along the direction relative to the origin?. What is its angular momentum 10. Figure 2 shows a 5.00-kg beam 2.00 m long that is used to support a kg sign by means of a cable attached to a building. What is the tension exerted by the beam on the cable? 40º JOE S JOE S DINNER Figure 2 Page 3 of 6

4 Part B: (Answer ONLY 4 questions - each question is worth 10 marks) QUESTION 1 a) A particle undergoes the following consecutive displacements: 3.50 m south, 8.20 m northeast, and 15 m west. What is the resultant displacement? [4] b) A golf ball is hit off a tee at the edge of a cliff. Its x and y coordinates as functions of time are given by the following expressions: x = (14.0 ms -1 )t and y = (8.00 ms -1 )t (4.90 ms -2 )t 2 i. Write a vector expression for the ball s position as a function of time, using the?i? j unit vectors and. [1] ii. By taking derivatives, obtain expressions of the velocity vector v as a function of time [2] iii. Use unit-vector notation to write expressions for the velocity, v and the acceleration, a of the golf ball, at t = 3.00 s. [3] QUESTION 2 Figure 3 shows a 5.00-kg object that is attached to a vertical rod by two strings. The object rotates in a horizontal circle at constant speed of 6.00 ms -1. Find the tension in a) the upper string and [5] b) the lower string. [5] Figure 3 Page 4 of 6

5 QUESTION 3 a) A 2.50-kg block is projected down a plane that makes an angle θ = 15 o with the horizontal with an initial velocity of 1.90 ms -1. If the coefficient of kinetic friction between the block and plane is 0.40, determine i) the initial kinetic energy; [1.5] ii) the friction force; and [1.5] iii) the distance of the block slide down the plane before coming to rest? [3] b) Two automobiles approach an intersection. One vehicle with a mass of 1200 kg is traveling with velocity 13.0 ms -1 toward the east. The other vehicle with a mass of 2000 kg is traveling north with velocity, v 2i. The vehicles collide in the intersection and stick together, and move at an angle of 55.0 o north of east, with final velocity, v f. Find i) final velocity, v f ; and [2] ii) initial velocity, v 2i. [2] QUESTION 4 a) A wheel of radius m is mounted on a frictionless, horizontal axis. The moment of inertia of the wheel about the axis is kgm 2. A light cord wrapped around the wheel supports a kg object as shown in the Figure 4. The object is released from rest. What is the magnitude of the acceleration of the kg object? Find i) the tension of the cord; and [5] ii) the acceleration of the object. [1] Page 5 of 6 Figure 4

6 b) A particle of mass m = kg and speed v 0 = 7.00 ms -1 collides and sticks to the end of a uniform solid cylinder of mass M = 4.00 kg and radius R = 30.0 cm as shown in Figure 5. If the cylinder is initially at rest and is pivoted about a frictionless axle through its center, what is the final angular velocity of the system after the collision? [4] Figure 5 QUESTION 5 (a) State Kepler s Third law [2] (b) A small satellite of earth has an orbital period of days and orbital radius of 2.15 x 10 7 m. Find (i) the mass of the earth; [4] (ii) the gravitational field of earth at the satellite; and [2] (iii) the linear speed of satellite. [2] - END OF QUESTION PAPER- Page 6 of 6

1 MR SAMPLE EXAM 3 FALL 2013

1 MR SAMPLE EXAM 3 FALL 2013 SAMPLE EXAM 3 FALL 013 1. A merry-go-round rotates from rest with an angular acceleration of 1.56 rad/s. How long does it take to rotate through the first rev? A) s B) 4 s C) 6 s D) 8 s E) 10 s. A wheel,