2017年3月15日 星期三

F2 IS 2nd Term WS04 9.4B Answers

2nd Term WS 04
Submission date_____________
Name______________________
Class & no.2 _________(     )
 
9.4 B    Action and reaction (P.28-32)
i     Words to know:

English term
Write the words again
Chinese term
1
Action-reaction pair

作用力和反作用力
2
Equal

相同
3
Opposite

相反
4
Eject

噴射
5
Launch

發射
6
Overcome

克服

i     Fill in the blanks:
1      When an object exerts a force on another object, it experiences an equal force in the
         opposite direction at the same time. These two forces are called an      action-reaction pair.
2      During a rocket launch, a large amount of hot gas is ejected downwards
from the rocket. The ejected gas produces an equal force that pushes the rocket upwards.
The great pushing force overcome the force of gravity acting on the rocket.
3       During a water rocket launch, the water is ejected downwards from the rocket. The ejected
         water produces an equal force that pushes the water rocket upwards.

i     Multiple choice: Circle the letter of the best answer for each question.
1.      When an inflated balloon is released, it will fly away. We can explain this in terms of
A. Friction                B. action and reaction               C. weightlessness                     D. gravity

2.       What forces does a rocket have to overcome when it is launched from Earth?
(I)                 Force of gravity
(II)               The pushing force due to the hot gas coming out from the rocket engine
(III)             Air resistance

A. (I) only                  B. (III) only                   C. (I) and (II) only                 D. (I) and (III) only





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