NAME NUMER SEC. PHYCS 101 SUMMER 2001/2002 FINAL EXAME:24/8/2002 PART(I) 25% PART(II) 15% PART(III)/Lab 8% ( ) 2.5 Q1 ( ) 2 Q2 Q3 Total 40% Use the followings: Magnitude of acceleration due to gravity is 10/s 2 Cos(37 )=sin(53 )=0.8, Cos(53 )=sin(37 )=0.6 PART (I): 10 MULTIPLE CHOICE QUESTIONS (25 Marks) Q1: A 0.5 kg football is kicked at ground level with initial speed of v 0 at an angle θ above the horizontal. If the ball reached a axiu height of y ax = 8, then the change in the ball s kinetic energy (in J) between point A and point is: A v 0 θ y ax (A) -25 () -40 (C ) -50 (D) -60 Q2: A ass M = 10 kg is being pulled upward with constant acceleration a = 2 /s as shown in the figure. The agnitude of tension (in N) in the sting is: (A) 60 () 120 (C ) 180 (D) 240 M a=2/s 2 Q3: A 5 kg ass is connected to a spring (k = 2000 N/) by a light string that passes over a assless and frictionless pulley as shown in the figure. If the ass is released fro rest when the spring is unstretched, then the axiu extension (in ) caused to the spring is: (A) 0.05 () 0.1 (C ) 0.2 (D) 0.5 x 5kg Q4: A 0.3 kg rubber ball is thrown horizontally towards a wall with a speed of 20/s and rebounds horizontally (returns) with the sae speed. The agnitude of ipulse (in N/s) by the wall on the ball is: (A) 4 () 8 (C ) 12 (D) 16 1
Q5: A wheel of radius 0.8 is rotated fro rest at constant acceleration and reached an angular velocity of 10 rad/s in 20 s. The radial acceleration (in /s 2 ) for a point on the wheel s ri is: (A) 0.25 () 0.3 (C ) 0.4 (D) 0.75 Q6: A rigid unifor disk ( I c =MR 2 /2) of radius R = 2 and ass M =10 kg. A ass = 2 kg is fixed to it s ri as shown in the figure. If the syste rotates about the disk s center with angular speed 6 rad/s, then the syste s rotational kinetic energy (in J) is: M 2 (A) 56 () 224 (C ) 504 (D) 896 F 1 =50N Q7: Two forces of agnitude 50 N, acted on a solid cylinder of radius r = 0.5 and oent of inertia I = 10 kg. 2 as shown in the figure. If the cylinder sits on a frictionless surface and starts fro rest, then its angular velocity (in rad/s) after 2 s is: (A) 5 () 10 (C ) 15 (D) 20 F 2 =50N 0.5 a Q8: Two blocks, as shown in the figure, are connected by a assless string passing over a pulley of radius 0.2 and oent of inertia I. If all surfaces are frictionless and the agnitude of the blocks acceleration is a = 0.5 /s 2, then the oent of inertia of the pulley (in kg. 2 ) is: 3kg 6kg (A) 0.12 () 0.36 (C ) 1.08 (D) 2.52 37 Q9: A unifor wooden rod of ass M = 2 kg and length L = 1 pivoted at its center (I c =ML 2 /12). A 0.5 kg clay ball is oving horizontally at speed v = 20 /s struck the rod end as shown in the figure. If the ball sticks with the rod after the collision, then the angular speed (in rad/s) of the syste after the collision is: v L (A) 4.28 () 8.57 (C ) 12.85 (D) 17.14 Q10: A 10 kg and 4 long unifor bea is pivoted to a wall and supported fro the iddle by a cable as shown in the figure. If a ass = 50 kg is hanged 1 fro the rod top, then the agnitude of the tension (in N) in the supporting cable is: (A) 300 () 412.5 (C ) 525 (D) 637.5 cable 37 2 2
PART (II): 3 SUJECTIVE QUESTIONS (15 Marks) Q1: A 2 kg block is set into otion up a rough (µ k = 0.4) inclined plane with initial speed of 20 /s as shown in the figure. Find: (1)- the acceleration of the block as it slides up the incline. (2)- the speed of the block as it leaves the incline (v ). (3)- the axiu height reached (y ax ). (4)- the horizontal distance (d) traveled by the block. 20/s 2kg 37 3.6 d y ax 3
PART (II): /Continue Q2: A ass =2 kg is pushed 0.4 against a spring of k = 500 N/ as shown in the figure. Then the ass is released fro rest on a frictionless track except for the portion between point A and point, which has a length of 2. and µ k = 0.25. While the ass traveling on the track it hits another ass M = 1 kg resting on the track. The two asses stick together after collision. Find: (1)- the energy that lost due to friction as the block slides fro A to. (2)- the speed of ass just before collision. (3)- the coon speed of the two asses just after collision (4)- the axiu height reached (y ax ). 0.4 2 resting M y ax A 4
PART (II)/ Continue Q3: A solid sphere of ass = 6 kg and radius r = 0.25 (I c = 2r 2 /5) rolls without slipping along the track shown in the figure. The sphere starts fro rest at height h = 1.4 R where R = 0.7 is the radius of the circular part of the track. At point, find 1.4R r R= 0.7 (1)- the sphere s center of ass speed (v ). (2)- the spheres center of ass radial acceleration. (3)- the noral force exerted fro the track on the sphere. 5
PART (III)/Lab.: 4 QUESTIONS (8 Marks) Q1: A car is oving with constant speed. If a student easured the its speed and obtained the following values; v 1 = 20 /s, v 2 = 20.5 /s and v 3 = 19.5 /s, then the percentage error in easuring the car s speed is: %error in v= Q2: In the free fall experient, a student obtained the following graph between the Y 1/2 and t. If the vertical distance Y varies with tie as: Y=(g/2)t 2, then the acceleration due to gravity g (in /s 2 ) is: Y 1/2 ( 1/2 ) 2.0 1.5 1.0 0.5 g= ( ) /s 2 0 0 0.2 0.4 0.6 0.8 Tie t(s) Q3: Newton s otion experient, a student obtained the following graph between the syste acceleration (a) and 2. If the total ass of the syste is kept constant at M T =2kg and a varies with 2 as: a= 2 g/m T, then the acceleration due to gravity g (in /s 2 ) is: g= ( ) /s 2 Q4: A student has recorded the following data for the force (F) and the extension (X) cased by F in a spring. Plot these data and deterine the spring constant (k) where F=kX. F(N) X() 1 0.1 2 0.25 3 0.3 4 0.35 5 0.5 acceleration a (/s 2 ) 5 4 3 2 1 0 0 0.2 0.4 0.6 0.8 1.0 2 (kg) k= ( )N/M 6