PHY110-APRIL 2006

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5304-1CONFIDENTIAL AS/APR 2006/PHY110

UNIVERSITI TEKNOLOGI MARAFINAL EXAMINATION

COURSECOURSE CODEEXAMINATIONTIME

MECHANICS 1PHY110APRIL 20063 HOURS

INSTRUCTIONS TO CANDIDATES1 . This question paper consists of two (2) parts : PART A (20 Questions)PART B (7 Questions)2. Answer ALL questions from all two (2) parts.

i) Answ er PART A in the Objective Answ er Sheet,ii) Answ er PART B in the Answ er Booklet.

3. Do not bring any material into the examination room unless permission is given by theinvigilator.4 . Please check to make sure that this examination pack consists of:

i) the Que stion Paperii) an Answer Bo oklet -prov ided by the Fac ulty/Bran ch CampusHi) an Objective Answ er Sheet - provided by the Faculty / Cam pus

DO NOT TURNTHISPAGEUNTILYOU ARE TOLD TO DO SOThis examination pa per consists of printed pages Hak Cipta Universiti Teknologi MARA C O N F ID E N T IA L

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CONFIDENTIAL 2 AS/APR 2006/PHY110

PART A (30 MARKS)TAKE THE ACCELERATION DUE TOGRAVITY 9 8m s2.1 . Wh ich of the following is not a base quantity?

A. Electric currentB. VelocityC. Amo unt of substanceD. Luminous intensity-3 -32. The density of aluminum block is 2.7 g cm . W hat is this value in kg m ?

A. 27 kg m"3B. 270 kg m"3C. 2700 kg m"3D. 27000 kg m"3

3. W hich of the following quantity-unit pair has the wrong unit?1A. momentum : N m s

1B. velocity : m sC. Impulse : N sD. Power : J s"4. An object is released to fall freely from the top of a building . After releasing it, thevelocity

A. is zeroB. remains constantC. decreases constantlyD. increases constantly5. A stone is thrown upw ard with a velocity of 30 m s . After 2 s its velocity will be

A. 10 .4 m s" 1B. 15.5 m s" 1C. 28.7 m s"1D. 49.6 m s"1

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6. Car A moves with a velocity of 80 km h" due north while car B moves with a velocity60 km h due east. W hat is the velocity and direction of car A relative to car B?A. 100 km h"1 : W 4 5 NB. 120 km h"1 : W 4 5 NC. 100 km h"1 : W 53 ND. 120 km h"1 : W 53 N

7. A m an walks 300 m due east in 20 minutes. Then he wa lks 200 m due west in25 minutes. The average speed the man has done isA. 7 m s"1B. 9 m s"1C. 1 1 m s"1D. 13 m s" 1

8. An object is thrown upward from earth's surface with a velocity u. Wh ich one of thefollowing statement is true in describing the energy transformation of the object as itrises?A. The total energy of the object increases.B. The kinetic energy decreases and the potential energy increases.C. The kinetic energy increases and the potential energy decreases.D. Both the kinetic and potential energy increases.

9. A bullet is shot with a velocity u at an angle 0to the horizontal an d hit the ground tseconds later. Wh ich of the following is true in describing the m otion?A. As 0increases twill be shorter.B. As 0increase s f will be longer.C. As 0increases r remain unchange d.D. As 0 increases the horizontal distance (Range) remains unchanged .

10. W hich of the following statement is true about elastic collisions?A. In elastic collision the total mom entum and the total kinetic energy is conserved.B. In elastic collision the total mom entum is conse rved wh ile the total kinetic energyis not conserved.C. In elastic collision the total momen tum is not conse rved wh ile the total kineticenergy is conserved.D. In elastic collision the total momen tum and the total kinetic energy is notconserved.

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1 1 . Object A of mass 500 g moves with a velocity of 5 m s" and hit object B of mass 300 gwh ich is at rest. After the collision both objects joined and move together. Determ inethe comm on velocity of the combined objects.A.B.C.D.

2 .1 m s3.1 m s4.1 m s5.0 m s

1 2. A wooden block is pushed by a constant horizontal force of 40 N and the block moveswith a uniform velocity 1.5 m s " . Find the power that has been used by this force.

13.

A.B.C.D.

50 W60 W70 W80 WGiven vectorAA.B.C.D.

-16-101610

4/ +5]+3k and B = 3i 2j +2k. Find A.B)

14. FIGURE 1 , shows blockX of mass 5 kg is pulled by a force F (80 N). The pulling forceF is inclined 25 to the horizontal and the coefficient of friction between the block andthe surface is 0.2. If the object moves 3 m, determine the work done by forceF .A.B.C.D.

200 J208 J2 1 5 J220 J

FIGURE 1

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18. How much energy is needed to stop a car of mass 1 000 kg which is moving with avelocity of 20 m s" ?A. 150 kJB. 200 kJC. 220 kJD. 250 kJ

Ques tion 1 9 -2 0 :A stone is thrown horizontally with a velocity u= 20 m s from the top of a building which is30 m high (FIGURE 3).

/\

30 m

v< - R >

FIGURE 319. Wh at is the time of flight of the stone before it reaches the grou nd.

A. 1.8 sB. 2.0 sC. 2.3 sD. 2.5 s20 . Wh at is the horizontal distance,R of the object.

A. 50 mB. 55 mC. 60 mD. 65 m

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PART B (70 MA RKS)QUESTION 1a) Define

i) displacement

ii) velocity(1 mark)

(1 m ark)b) A car which is initially at rest moves in a straight line PQR S. The movem ent of the carcan be represented by a graph of velocity versus time as shown inFIGURE 4. Find,

i) the accelerations at segment PQ, QR and RS.

ii) the total distanc e traveled by the car

_ /Velocity m s )

(3 marks)

(2 marks)

Time (s)FIGURE4

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QUESTION 2

a) W hat is mean t by a vector quantity? Give four exam ples of vector quan tities. (3 marks)b) FIGURE 5 shows 3 vectors F1t F2 and F3 on the x-y plane and their magnitudes aregiven in arbitrary units.

i) W rite dow n eac h vector in unit vector notation.

ii) Find the magnitud e and direction of the resultant of the three vectors .

F2=1

(314 marks)

(51/2 marks)

F, = 28

FIGURE 5

QUESTION 3a) A bullet is fired from a canno n with a velocity of 250 m s" at an angle of 40 above thehorizontal. Calculate

i) the time taken for the bullet to reach the ground,

ii) the horizontal distance the bullet reach the ground.(2 marks)

(2 marks)b) A car traveled 2 km west and then 4 km north. Sketch the vector diagram anddetermine

i) the magn itude and

ii) the angle of the car's total displacem ent from its starting point.(21 /2marks)

(1 4 marks)


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QUESTION 4a) FIGURE 6 shows an object P of mass 1 kg on a horizontal table connected by a light

string that passes over a smooth pulley to an object Q of mass 3 kg which is hungvertically. The coe fficient of friction between object P and the table is 0.25. Object Pwhich is 1.0 m from the pulley is released from rest. Determinei) the tension in the string during the motion. (3 marks)ii) the acce leration of the object. (1 marks)iii) the velocity of object P just before it hits the pulley. (1 4 marks)

p 1.0 mI 1n tiFIGURE6

b) An object is thrown vertically upwards with a velocity of 15 m s" from the top of abuilding which is 1 5 m high. Determinei) the velocity 2 s after it is throw n. (1 4marks)ii)) the time taken for the object to reach the ground. (51/2 marks)iii) the total distance traveled by the object from it is thrown until reached the ground.

( r emar ks )

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QUESTION 5.-I

a) Sphere of massm = 300 g is traveling at a velocity of 2 m s to the right. Sphere 1hits sphere 2 of mass m 2 = 200 g which is at rest. If the collision is assumed to beelastic, determine the velocity of both spheres after the collision. (7 marks)b) A ball of mass 2 kg is released from a height of 8 m and hits a horizontal floor. It isfound that the ball rebound upward to a height of 3 m. Find the magn itude of theimpulse on the ball. (6 marks)QUESTION 6

a) Definei) gravitational potential energy (1 m ark)ii) kinetic energy of an object (1 m ark)

b) A bullet of ma ss 25 g is fired into a block of wo od of mass 925 g located on ahorizontally smooth surface . The block is attached to a spring with spring constant,k = 650 N m~ as shown inFIGURE 7. After impact the bullet remains in the block andboth objects compressed the spring by a distance of 10 cm. Determine the initialvelocity of the bullet. (5 marks)

k f W \ fFIGURE 7


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QUESTION 7a) A ball is released freely from the top of a building. At a height of 25 m the ball was

found to fall at a velocity of 20 m s . By using the principle of conservation of energy,determinei) the height of the building. (21/2marks)ii) the velocity of the ball just before it strikes the ground . (21/4 m arks)

b) FIGURE 8 shows a 30 kg block on an inclined smooth plane being pulled by a force of120 N, causing the block to move 5 m in 6 s. Findi) the work done to move the block for the distance of 5 m. (2 marks)ii) the power that has been used by this force. (2 marks)

FIGURE 8

END OF QUESTION PAPER


PHY110-APRIL 2006

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