PHYSICS QUESTIONS & ANSWER (1)

1. When a box of mass 45kg, is given an initial speed of 5ms-1 it slides along a horizontal floor a distance of 3m before coming to a rest. what is the coefficient of kinetic friction between the box and the floor? (g = 10ms-2)
   A. 5/6
   B. 5/12
   C. 1/3
   D. 2/336
   137
2. The diagram above shows a solid figure with base PQ and center of gravity G on an inclined plane. Which of the following statements is correct
   A. The solid will fall over if the vertical line through G lies outside the base
   B. The solid will fall over if the vertical line through lies inside the base
   C. The solid will not fall over if the vertical line through G lies outside the base
   D. The solid can never fall over
3. If an object just begins to slide on a surface inclined at 30o to the horizontal, the coefficient of friction is
   A. √3 B. √3/2 C. 1/√2 D. 1/√3
4. A 90cm uniform lever has a load of 30N suspended at 15cm from one of its ends. If the fulcrum is at the center of gravity, the force that must be applied at its other end to keep it in horizontal equilibrium is
   A. 15N
   B. 20N
   C. 30N
   D. 60N
5. A 100kg box is pushed along a road with force of 500N. If the box moves with a uniform velocity, the coefficient of friction between the box and the road is
   A. 0.4
   B. 1.0
   C. 0.8
   D. 0.5
6. If a cage containing a truck of coal weighing 750 kg is raised to a height of 90 m in a minute, what is the total power expended? [g = 10 ms-2]
   A. 11.50 kW
   B. 12.60 kW
   C. 11.25 kW
   D. 12.10 kW422
7. A uniform rod PQ of length 1m and mass 2kg is pivoted at the end P. If load of 14N is placed at the center of the rod, find the force that should be applied vertically upwards at Q to maintain the rod at equilibrium horizontally [g = 10ms-2]
   A. 68N B. 28N C. 17N D. 7N
   814
8. The resultant force of a couple is ………?
   A. Infinity
   B. Zero
   C. One
   D. Half
9. Which of the following statements are TRUE about frictional force?
   i. it is always a disadvantage
   ii. it is sometimes a disadvantage
   iii. it always exists where there is a relative motion of two bodies that are in contact iv. it is sometimes very useful
   A. i, iii only
   B. i, iv only
   C. ii, iii only
   D. iii, iv only
10. An object of mass 80 kg is pulled on a horizontal rough ground by a force of 500 N. Find the coefficient of static friction. [g = 10 ms-2]
    A. 0.8 B. 0.4 C. 1.0 D. 0.6
11. If a load of mass 10N stretched a cord by 1.2cm, what is the total work done?
    A. 6.0 x 10-2J
    B. 7.6 x 10-2J
    C. 1.8 x 10-2J
    D. 6.6 x 10-2J
    453
12. The value of F in the figure above when in equilibrium is
    A. 10N B. 12N C. 20N D. 27N454
    455
13. If the system above is in equilibrium, the tension in the string Q is
    A. 11N B. 9N C. 4N D. 6N
14. Which of the following could be effectively used to reduce friction?
    A. kerosene
    B. grease
    C. water
    D. petrol
15. An object is moving with a velocity of 5m-1. At what height must a similar body be situated to have a potential energy equal in value with kinetic energy of the moving body?
    A. 25.0m
    B. 20.0m
    C. 1.3m
    D. 1.0m648
16. If a pump is capable of lifting 5000kg of water through a vertical height of 60m in 15 min, the power of the pump is
    A. 2.2.5 x 10 5Js-1
    B. 2.5 x 104Js-1
    C. 3.3 x 103Js-1
    D. 3.3 x 102Js-1
    649
17. Calculate the work done when a force of 20N stretches a spring by 50mm.
    A. 0.5J
    B. 1.5J
    C. 2.0J
    D. 2.5J
18. Which of the following statements are correct about an object in equilibrium under parallel forces? i. the total clockwise moments of the forces about any point equals the total anti-clockwise moments about the same point.
    ii. the total forces in one direction equals the total forces in the opposite direction.
    iii. the resolved components along the x-axis equals the resolved components along the y-axis.
    A. i and ii only
    B. i and iii only
    C. ii and iii
    D. i, ii, and iii only
19. A body falls freely under gravity (g = 9.8ms-2) from a height of 40m on to the top of a platform 0.8m above the ground. Its velocity on reaching the platform is
    A. 784ms-1
    B. 80ms-1
    C. 78.4ms-1
    D. 39.2ms-1
    E. 27.7ms-1
20. Two masses 40g and 60g respectively, are attached firmly to the ends of the light meter rule. The center of gravity of the system is
    A. at the mid-point of the meter rule
    B. 40cm from the lighter mass
    C. 40cm from the heavier mass
    D. 60cm from the heavier mass
    E. indeterminate because the meter-rule in

ANSWERS

1.A

2. D

3. D

4. B

5. D

6. C

7. C

8. B

9. C

10. D

11. A

12. C

13. B

14. B

15. C

16. C

17. A

18. A

19. E

20. C