PHYSICS FIRST TERM EXAMINATION SS 2

Examination malpractices may lead to a repeat of the subject or suspensions don’t be involved.

SUBJECT: PHYSICS                                                TIME: 2HRS             CLASS: SS  2

SECTION A (OBEJECTIVES)

Instruction: Answer ALL questions in this section. All question carries equal mark

Constant: Unless otherwise stated, used these constant g=10m/s2

1. Determine the distance between S (3,4,-5) and T (2,1,0) (a) 5.8 (b) 5.9 (c) 6.0 (d) 6.2
2. Which is the following are derived units? i. metre ii. Coulomb iii. Kilogram iv. Ampere v. joule (a) I and iii only (b) ii and v only (c) ii,iv and v only (d) all of them
3. A motorist travelling at 72km/h, on siting a STOP sign applies the brakes such that under constant deceleration the car is brought to a stop within a distance of 50m. the magnitude of the deceleration is (a) 50m/s2 (b) 25m/s2 (c) 8 m/s2 (d) 4 m/s2
4. A car took off from rest moves with a uniform acceleration of 6m/s2. The distance it covers in the fourth second of the motion is (a) 21m (b) 27m (c) 48m (d) 96m
5. An object is released from rest at a height of 20m. Calculate the time it takes to fall to the ground (g= 10m/s2) (a) 1s (b) 2s (c) 3s (d) 4s.
6. For a projectile the maximum range is obtained when the angle of projection is; (a) 600 (b) 300 (c) 450 (d) 900
7. A ball is thrown vertically upwards from the ground with an initial velocity of 20m/s. the maximum height reached by the ball is

• 5m (b) 10.0m (c) 20.0m (d) 22.5m

8. A body of mass 5kg moving with a velocity of 20m/s due south hits a stationary body of mass 3kg. If they move together after collision with a velocity v due south, the value of v is (a) 20.0m/s (b) 15.0m/s (c) 12.5m/s (d) 12.0m/s
9. When taking a penalty kick, a footballer applies a force of 100N for a period of 0.03s. If the mass of the ball is 150g, calculate the speed with which the ball moves off (a) 50m/s (b) 25m/s (c) 20m/s (d) 10m/s
10. A man walks 5km south and then 3km in the direction 600 west of south. His distance from the starting point is (a) 7.00km (b) 7.50km (c) 8.00km (d) 10.72km
11. The resultant of two forces acting on an object is maximum when the angle between them is (a) 1800 (b) 900 (c) 450 (d) 00
12. 8N (north)

6N (east)

A body is acted upon by the forces 6N and 8N as shown in the diagram above. The resultant of the forces is

(a) 10N in the direction N370E (b) 10N in the direction N530E (c) 10N in the direction N370W (d) 10N in the direction N530W

13. 50g of fuel is burnt each second in a rocket engine and ejected as a gas with a speed of 4,000m/s. the thrust on the rocket is (a) 20N (b) 80N (c) 200N (d) 500N
14. A uniform metre rod of weight 40N has a piece of metal of weight 20N attached to one of its ends. The centre of gravity of the system from the weight end is (a) 8.4cm (b) 16.7cm (c) 25.0cm (d) 33.3cm
15. The equilibrant of a system of forces is (a) equal and opposite to the resultant of the forces (b) the force which has the same effect as the system (c) equal to resultant of the system (d) the force that makes the system unstable
16. Two forces forming a couple are separated by a distance of 25m, if one of the forces equal 40N, what is the moment of the couple? (a) 1000Nm (b) 500Nm (c) 10Nm (d) 5Nm
17. Two forces each of magnitude 10N acts in opposite directions at the end of a table. If the length of the table is 50cm.Find the moment of the couple on the table (a) 0.5Nm (b) 5Nm (c) 50Nm
18. A uniform metre rod of mass 1.5kg is pivoted at one end. A weight of 7N is placed at the centre of the rod. The vertical force which should be applied at the other end to maintain the rod in equilibrium in the horizontal position is (a) 22N (b) 11.0N (c) 10.5N (d) 8.5N
19. When a body is acted upon by several forces and it does not accelerate or rotates, the body is said to be in (a) space (b) equilibrium (c) motion (d) uniform retardation
20. Consider the three forces acting at a point O and is in equilibrium as shown below. Which of the equations is/are correct?

P3                           O          θ1          P1

θ2

P2

1. P1cos θ1= P1cos θ2           P3= P1cos θ1+ P2cos θ2       iii. P1sin θ1= P2cos θ2          (a) I only (b) II only (c) III only (d) II and III only
2. Weights of 0.2N and 0.5N are placed at the 30cm and 80cm marks respectively on a uniform metre rule balances horizontally on a knife edge at the 60cm mark, the weight of the metre rule is (a) 0.1N (b) 0.3N (c) 0.4N (d) 0.7N
3. A pendulum bob, executing simple harmonic motion has 2cm and 12Hz ass amplitude and frequency respectively. Calculate the period of the motion (a) 2.00s (b) 0.83s (c) 0.08s (d) 0.06s
4. What is the angular speed of a body vibrating at 50 cycles per seconds (a) 200πrads-1 (b) 400 πrads-1 (c) 100 πrads-1 (d) 50 πrads-1
5. A jet engine takes 20kg air per second at 150m. The air is compressed, heated and discharged at 500m/s. What force is developed in the engine? (a) 10,000N (b) 5,000N (c) 1000N (d) 500N

25. A 15kg mass, suspended from a ceiling is pulled aside with a horizontal force, F, as shown in the diagram below. Calculate the value of the tension T (g=10ms-2)

300 T

F

15kg

• 0N (b) 173.2N (c) 30.0N (d) 17.3

26. In the diagram below, the maximum potential energy of the swinging pendulum occurs at position(s) (a)1 and 5 (b) 2 and 4 (c) 3 0nly (d) 5 and 3

1                                   5

2                    4

3

27. The motion of a body is simple harmonic if the: (a) acceleration is always directed towards a fixed point (b) path of motion is a straight line (c) acceleration is directed towards a fixed point and proportional to its distance from the point (d) acceleration is proportional to the square of the distance from a fixed point
28. The period of oscillatory motion is defined as the (a) average of the time used in completing different numbers of oscillations (b) time to complete a number of oscillations (c) time to complete one oscillation (d) time taken to move from one extreme position to another
29. In the diagram below XY represents a plank used to lift a load from a point X on the ground onto a horizontal platform YP.

Y   P

X                         Z

What is the velocity ratio of the plank? (a)  (b)(c) (d)

30. A meter rule pivoted at its centre has masses m1 and m2 placed at the 20cm and 65cm marks respectively. If the meter rule balances horizontally, the ratio m2/m1 is (a) 2 (b) 3/2 (c) 2/3 (d) ½
31. A uniform metre rod of mass 1.5kg is pivoted at one end. A weight of 7N is placed at the centre of the rod. The vertical force which should be applied at the other end to maintain the rod in equilibrium in the horizontal position is (a) 22.0N (b) 11.0N (c) 10.5N (d) 8.5N
32. A machine has efficiency of 75%. The work done when the machine is used to raise a load of 50kg through a vertical distance of 6m is (a) 4000J (b) 3000J (c) 2250 J (d) 500J
33. A machine with an efficiency of 60% is used to overcome a load of 60N through the application of a force of 40N. the mechanical advantage of the machine is (a) 0.4 (b) 0.9 (c) 1.5 (d) 2.5
34. The velocity ratio of the machine in question 33 is (a) 4.17 (b) 2.50 (c) 1.50 (d) 0.67
35. 500J of work is required by a machine to raise a load of 250N through a vertical distance of 1.6m. the efficiency of the machine is (a) 80% (b) 75% (c) 67% (d) 50%
36. The velocity ratio of an inclined plane of angle ɵ is (a) sin ɵ (b) tan ɵ (c) 1/sin ɵ (d) 1/tan ɵ
37. A pulley system has a velocity ratio of 6 and an efficiency of 75%. The effort needed to lift a load of mass 135kg is (a) 1013N (b) 300N (c) 225N (d) 30N
38. The efficiency of a wheel and axle system is 80% and the ratio of radius of wheel to radius of the axle is 4 : 1, In order to lift a mass of 20kg,the effort required is (a) 60N (b) 62.5N (c) 32.5N (d) 250
39. A screw jack has a pitch of 0.5cm and a tommy bar of length 20cm. the velocity ratio is (a) 40π (b) 40/π (c) 80π (d) 80/π
40. Two forces 12N and 16N are inclined at an angle ϴ to each other, have a resultant which is parallel to the 16N force. The value of cos ϴ is (a) 1.0 (b) ¾ (c) ½ (d) 0
41. A man walks 5km south and then 3km in the direction 600 west of south. His distance from the starting point is (a) 7.00km (b) 7.50km (c) 8.00km (d) 10.72km
42. When a body is performing a simple harmonic motion, its acceleration (a) is constant (b) varies with displacement from equilibrium position (c) is zero (d) moves irregularly with time
43. When a simple harmonic motion is affected by severe air resistance, the motion is said to be (a) damped (b) forced motion (c) natural motion (d) sinusoidal
44. What is the angular speed (in rads-1) of abody whose frequency is 50Hz? (a) 200 π (b) 100 π (c) 50 π (d) 10 π
45. A ball of mass 100g falls from a height of 5m onto a floor and rebounds into a height of 3m. What energy is lost as a result of the impact on the floor? (a) 2J (b) 20J (c) 100 J (d) 1000 J
46. A body of mass 10kg, moving with velocity of 10m/s, hit a stationary body and had its direction reversed and the velocity changed to 7.5m/s in 5 seconds. Calculate the force of impact (a) 3.5N (b) 35.0N (c) 175.0N (d) 875.0N
47. In elastic collision, (i) energy is conserved (ii) energy is decreased (iii) energy is increased (iv) linear momentum is conserved (a) I only (b) ii only (c) iii only (d) I and iv only
48. Calculate the force required to impart an acceleration of 5m/s2 to a mass of 10kg (a) 50N (b) 30N (c) 60N (d) 100N
49. Which of these is not correct? Simple examples of first order levers are (a) crowbar (b) claw hammer (c) pliers (d) wheel barrow
50. A stone is thrown vertically into the air with an initial upwards speed u, at what time will the stone return to the starting point (a) u/g (b) 2u/g (c) u2/g (d) 2u2/g

SECTION B (THEORY)

Instruction: Attempt any THREE questions in this section

1. (a) Show that efficiency E, the force ration (MA) and the velocity ratio (VR) of a machine are related by the equation 4marks

(b) Three coplanar forces act simultaneously at a point as shown below

107N

80N

60°

100N

Find the resultant of the forces and its direction.                                        6marks

2. (a) A bus moves from rest with a uniform acceleration of 2m/s2 for the first 6s. It maintained the velocity reached for 30 seconds and was brought to rest after 5 seconds when the brake was applied. Find for the motion: (I) the maximum velocity reached (ii) the total distance travelled (iii) the average speed for the whole journey (iv) the average retardation

(Draw the velocity time graph of the motion using the information above)         6marks

(b)The period of oscillation of a simple pendulum is 2.18 secomds. Calculate; (I) the time to complete 50 oscillations (ii) the length of the simple pendulum {g=10m/s2)                                          4marks

3. (a) An object is thrown vertically upwards with a velocity of 20m/s at an angle 30° to the horizontal. Calculate: (I) the maximum height reached (ii) the time taken to reach the maximum height (iii) the time of flight 5marks

(b) A uniform metre rule of weight 1.5N is supported at the ends as shown in the diagram below. Calculate the reactions at the supports when the weights 2N and 2.5 Nare placed at 0.2m and 0.75m marks respectively                              5marks

A                 2N               1.5N                              2.5N                              B

4. (a) A bullet of mass 100g is fired horizontally into a fixed wooden block with a speed of 20m/s. The bullet is brought to rest in the block in 0.1s by a constant resistance. Calculate the: (i) magnitude of the resistance (ii) the distance moved by the bullet in the wood                     4marks

(b) State Newton’s second law of motion                                           2marks

(c) a tanker of mass 20000kg at 10m/s collides and sticks to a bus of mass 5000kg travelling at 20m/s   in opposite direction. What is their common velocity after collision?                                                                                                   4marks

5. (a) A machine with efficiency 80% and velocity ratio 5 lifts a weight off 1500N through a vertical height of 5m. Calculate: (I) the mechanical advantage of the machine (ii) the effort needed to lift the load (iii) the work done by the effort 6marks

(b) State the law of conservation of linear momentum                      2marks

(c) What is simple harmonic motion?                                                            2marks