ASSIGNMENT BOOK Unit 9 Part 2 Part 2 Integrated Exercises (Unit Test) A. True or False (Total 20 marks; 2 marks each) Study the following statements. Put a ‘ T ’ in the box against a correct statement and a ‘F’ against an incorrect statement. 1.There are only two kinds of non-contact forces: magnetic force and force of gravity. T F 2.Weight is a kind of force. 3.Friction may be very useful to us. T

ASSIGNMENT BOOK Unit 9 Part 2 4.Action and reaction may be different in size. F T F T 5.The force that pushes a rocket upwards is due to the hot gas which moves downwards. 6.All rockets use liquid hydrogen as fuel. E 7.We use hydrogen as rocket fuel because it can reduce the loading of the rocket. E

ASSIGNMENT BOOK Unit 9 Part 2 F F T 8.A spacesuit must be made of a good conductor of heat. E 9.Space exploration is safe and low in cost. E 10.The spin-off products from space technology, such as dried food, cordless drills and smoke detectors, can benefit our lives. E

ASSIGNMENT BOOK Unit 9 Part 2 B.Multiple Choice Questions (Total 30 marks; 2 marks each) Write the correct answer to each question in the box provided. 1. Which of the following is NOT a force? A.friction B.mass C.weight D.gravity B

ASSIGNMENT BOOK Unit 9 Part 2 2. Two ring magnets are placed in such a way that they do not touch each other. magnet A magnet B

ASSIGNMENT BOOK Unit 9 Part 2 What force makes magnet A 'floats' in air? A.friction B.force of gravity C.electric force D.magnetic force D

ASSIGNMENT BOOK Unit 9 Part 2 3.Which of the following are non-contact forces? (1)friction (2)magnetic force (3)force of gravity A.(1) only B.(2) only C.(1) and (3) only D.(2) and (3) only D

ASSIGNMENT BOOK Unit 9 Part 2 4.The weight of an object is A.equal to its mass. B.the force of gravity pulling it by the Earth. C.the force of gravity pushing it by the Earth. D.the force of gravity pulling it by the Sun. B

ASSIGNMENT BOOK Unit 9 Part 2 C 5.An astronaut weighs less on the Moon than on the Earth because A.the Moon has no atmosphere. B.the astronaut is far away from the Earth. C.the force of gravity acting on the astronaut is smaller on the Moon. D.the Earth's force of gravity has no effect on the astronaut. E

ASSIGNMENT BOOK Unit 9 Part 2 C 6.Which of the following statements is INCORRECT? A.Friction can oppose the motion of a moving body. B.Friction can produce heat. C.Friction can only be reduced by lubricants. D.Friction can be measured by using a spring balance.

ASSIGNMENT BOOK Unit 9 Part 2 7.Friction can be reduced by using (1)lubricants. (2)an air cushion. (3)ball bearings. A.(1) only B.(1) and (2) only C.(2) and (3) only D.(1), (2) and (3) D

ASSIGNMENT BOOK Unit 9 Part 2 8.Which of the following statements correctly explains why a water rocket can move up?

ASSIGNMENT BOOK Unit 9 Part 2 A. As water is being pushed out of the rocket, the weight of the rocket decreases. The rocket therefore moves up. B.As water is being pushed out of the rocket, the force of gravity pulling the rocket decreases. The rocket therefore moves up. C.As water is being pushed out of the rocket, the rocket is also being pushed back by the water. The rocket therefore moves up. D.As water pushes the ground, the ground also pushes the water. The rocket therefore moves up. C

ASSIGNMENT BOOK Unit 9 Part 2 9.When a spacecraft is moving in space, it is not necessary to switch on the rocket engine because A.there is no air friction in space. B.the spacecraft is weightless in space. C.there is no oxygen in space. D.there is no force of gravity in space. A

ASSIGNMENT BOOK Unit 9 Part 2 D 10.The use of the two solid rocket boosters of a space shuttle is to provide A.extra liquid hydrogen for the space shuttle. B.extra liquid oxygen for the space shuttle. C.extra air for the space shuttle. D.extra pushing force for the space shuttle during lift-off. E

ASSIGNMENT BOOK Unit 9 Part 2 B 11. The danger of using hydrogen as fuel is that it is A.poisonous. B.too easy to burn. C.too light. D.colourless and odourless. E

ASSIGNMENT BOOK Unit 9 Part 2 C 12. The astronauts below are receiving training inside an aeroplane flying in a special path. What is the training for? A.training for landing on Earth B.training for working in space C.training for moving in a state of weightlessness D.training for handling accident

ASSIGNMENT BOOK Unit 9 Part Astronauts have to do exercise in the space shuttle regularly because A.astronauts will become fat easily in a state of weightlessness. B.astronauts' muscles will become weaker in a state of weightlessness. C.astronauts cannot eat much food in a state of weightlessness. D.astronauts' reaction will become slower in a state of weightlessness. B

ASSIGNMENT BOOK Unit 9 Part 2 The shiny surface of the visor can help A. protect the astronaut from being hurt by harmful radiation. B.protect the astronaut from being hurt by fast moving particles. C.maintain the body temperature of the astronaut. D.reduce heat transfer by conduction. C 14. Look at the picture below. E

ASSIGNMENT BOOK Unit 9 Part 2 D 15. Which of the following is NOT a spin-off product of space technology? A.bar code system B.cordless drill C.smoke detector D.television E

ASSIGNMENT BOOK Unit 9 Part 2 1.State three effects of the force exerted by each soccer player on the motion of the football. (6 marks) C.Question (Total 50 marks)

ASSIGNMENT BOOK Unit 9 Part 2 Player No. 10: _________________________________________ Player No. 3: _________________________________________ Goalkeeper: _______________________________________ It can start the motion of the football. It can change the direction of motion of the football. It can stop the motion of the football.

ASSIGNMENT BOOK Unit 9 Part 2 2. The diagram below shows a man trying to push a heavy box along the floor. The diagram below shows the main forces acting on the man, the box and the floor

ASSIGNMENT BOOK Unit 9 Part 2 (a) Put the correct number against the description of each force.(6 marks) Friction of the floor on the feet Friction of the floor on the box Push of the man on the box Friction of the box on the floor Friction of the feet on the floor Push of the box on the man NumberForce

ASSIGNMENT BOOK Unit 9 Part 2 1 and 2, 3 and 4, 5 and 6 He can push the box over some rollers. / He can add some lubricating oil on the floor. (b) Name all the action-reaction pairs shown in the diagram.(3 marks) (c) Suggest ONE method with which the man can push the heavy box with a smaller force. (2 marks)

ASSIGNMENT BOOK Unit 9 Part 2 stream-lined 3.(a)(i) Use an adjective to describe the shape of a rocket, a high speed train and a fish. (2 marks)

ASSIGNMENT BOOK Unit 9 Part 2 It can help reduce friction in air or in water. This action can help reduce friction as she dives into water. (ii) What is the advantage of possessing such a shape?(2 marks) (iii) A high diver stretched out her arms and legs in a straight line at the moment of diving into water. Why did she do that?(2 marks)

ASSIGNMENT BOOK Unit 9 Part 2 (b)(i)Study the diagram below. The water acts as a lubricant. The friction between the wheels and the road is reduced. The car therefore skids. Explain why the car skids when there is water on the road.(3 marks)

ASSIGNMENT BOOK Unit 9 Part 2 Grooves on tyres. (ii) What design of a car helps to prevent skidding on a wet road? (2 marks)

ASSIGNMENT BOOK Unit 9 Part 2 4.(a) Two students are pulling against each other using a length of rope with a spring balance at each end. If spring balance A reads 60 N, what will spring balance B read? (2 marks) 60 N Mary Peter BA

ASSIGNMENT BOOK Unit 9 Part 2 (c) This activity shows that action and reaction are ______________ in strength but ______________ in direction.(4 marks) equal opposite (b)The students then sit on trolleys. Peter pulls on the rope. Mary holds the rope but does not pull. Use arrows to show what will happen.(2 marks)

ASSIGNMENT BOOK Unit 9 Part 2 5. The figure below shows the structure of a rocket that uses liquid hydrogen as fuel. The rocket also carries its own supply of oxygen. The rocket has two stages. When each stage runs out of fuel, it is dropped off. satellite capsule 2nd-stage rocket 1st- stage rocket

ASSIGNMENT BOOK Unit 9 Part 2 A two-stage rocket can reach a higher speed. / A two-stage rocket can carry more cargo into space. It is because there is no oxygen in space. water (b)Why does the rocket have to carry its own supply of oxygen?(2 marks) (a)State TWO advantage of a two-stage rocket over a single stage rocket.(4 marks) (c) What is produced when hydrogen burns with oxygen?(2 marks) E

ASSIGNMENT BOOK Unit 9 Part 2 Advantage: Burning hydrogen is clean. / Its low density reduces the loading of the rocket. Disadvantage: It is too easy to burn. / Leakage is difficult to detect. (d) Give TWO advantage and ONE disadvantage of using hydrogen as fuel. (6 marks) E