F2 IS 2nd Term QZ 04: 9.4B anwers

Word Translation (6 marks)

i    Write down the English terms of the following Chinese terms:

	Chinese term	English term
1	作用力及反作用力	Action-reaction pair
2	噴射	Eject
3	相等	Equal
4	發射	Launch
5	相反	Opposite
6	克服	Overcome

Multiple Choice (4 marks)

Circle the letter of the best answer for each question.

1.     Which of the following statements about an action-reaction pair is INCORRECT?

A.   They are equal to each other.                  B.    They are in opposite directions.

C.   They act on two different objects.          D.    They occur one after another.

2.     The upward force on a rocket during its launch is caused by ___________________ .

A.   the hot gas ejected downwards from the rocket   

B.   the weight of the rocket

C.   the gravity of the Earth acting on the rocket         

D.   the gravity of the Moon acting on the rocket

3.     Which of the following statements concerning the balloon rocket shown below is correct?

A.    The air outside pushes the balloon to the left.

B.    The air inside pushes the balloon to the left. Then the balloon pushes the air out.

C.    The balloon pushes the air out. Then the air inside pushes the balloon to the left.

D.    The air inside the balloon and the balloon push each other in opposite directions at the same time.

4.    Which of the following diagrams correctly shows the forces acting on a space shuttle during lift off?

       A

Fill in the Blanks (10 marks)

1        When an object exerts a force on another object, it experiences an (1)equal

force in the (2)opposite direction at the same time. These two forces

are called an (3)action-reaction pair.

2        During a rocket (4)launch, a large amount of hot gas is (5)ejected downwards from the rocket. The hot gas produces an equal force that pushes the rocket (6)upwards and (7)overcome the force of gravity acting on the rocket by the Earth.

3      During the launch of a water rocket, the water is ejected (8)downwars from the water rocket. The ejected water produce an (9)equal force that (10)pushes the water rocket upwards and overcome the force of gravity acting on it by the Earth.

Challenging Questions (Bonus 2 marks)

The following diagram shows that Doraemon is flying. Use arrows to represent the action-reaction pair that causes him to fly. Use different colours to represent the forces and label the forces respectively.