Answers scheme (UP 2 ) physics form 4 2015

SECTION A

1. A 2. A 3. C 4. D 5. B6. D 7. C 8. C 9. C 10. B11. C 12. D 13. A 14. B 15. B16. D 17. B 18. D 19. D 20. A21. C 22. B 23. C 24. A 25. A

NO. ANSWERS SECTION B1 (a) The mass of the B cargo is larger [1mark]

(b) The volume of water displaced by ship B is bigger than ship A [1mark]

(c) The bigger the mass of the load , the bigger the volume of water displaced [1mark]

(d) (i) The buoyant force, the gravitational force (weight) [1mark]

(ii) F=W [1mark]

(e) The Archimedes Principle [1mark]

(f) sink deeper [1mark]

The density of the river water less than the seawater [ 1 mark ]

Total 8 marks

2. (a) Atmospheric pressure is the weight of air acts on a surface. It caused by air molecule

Collision on the surface. [1mark]

(b) Air pressure in the sticker decrease.

Have the different between pressure in the pump and the air pressure surrounding.

The force is produced

Force > mirror weight [4marks]

(c) (i) (Use F = PA)

Force is produced by pump S = 4.0 x 104 x 0.0025 = 100 N

Force is produced by pump M = 4.5 x 104 x 0.0040 = 180 N

Force is produced by pump T = 6.0 x 104 x 0.0035 = 210 N [3marks]

(ii) mirror weight = ρVg

= 2.5x10 3 x 1.5 x 0.5 x 0.01 x 10

= 187.5N [2marks]

(d) Pump T is choosen because force is produced bigger than mirror weight. [2marks]

Total 12 marks

3. (a) (i) P = F/A

= 20 / 5 x 10-4

= 40 kPa [ 2 marks ]

(ii) 40 kPa [ 1 mark ]

(iii) F = P A

= 40 x 103 x ( 50 x 10-4)

= 200 N [ 2 marks ]

(iv) F2 = ( A2/A1 ) F1 [ 2 marks ]

F2 = 10 F1

(b) Pascal’s Principle [ 1 mark ]

(c) Incompressible [ 1 mark ]

( d) Hydraulic brake [ 1 mark ]

Total 10 marks