I.S homework 2

8. Which of the following about the alkalinity and acidity of the substances is correct?
Highly acidic Mildly acidic Neutral Mildly alkaline Highly alkaline (1 分)

A. Lemon juice Acid rain Tap water Toothpaste Oven cleaner
B. Car battery acid Lemon juice Pure water Baking soda Oven cleaner
C. Juice in stomach Vinegar Pure water Oven cleaner Bleaching agent
D. Apple juice 7-up Sea water Baking soda Bleaching agent


9. Which of the following matchings between sense organs and receptors is correct?
Sense organ Receptor (1 分)

A. Eye Lens
B. Nose Nostrils
C. Ear Ear-drum
D. Tongue Taste buds


10. Which of the following is NOT a property of alkalis? (1 分)

A. They are corrosive.
B. They can neutralise acids.
C. They feel soapy.
D. They taste sour.


11. Which of the followings is a force?
(1) Tension
(2) Compression
(3) Friction (1 分)

A. (2) only
B. (1) and (2) only
C. (1), (2) and (3)
D. (1) only


12. Force is measured in (1 分)

A. seconds.
B. Weber.
C. hertz.
D. newtons.


13. The mass and weight of an astronaut on the moon is 60 kg and 100 N respectively. What are the mass and weight of the astronaut on the Earth? (1 分)

A. 60 kg and 100 N
B. 10 kg and 100 N
C. 60 kg and 600 N
D. 10 kg and 600 N


14. Which of the following options is/are the mean of reducing friction?
(1) Adding lubricant
(2) Using ball-bearings
(3) Using air cushion (1 分)

A. (1) and (2) only
B. (1), (2) and (3)
C. (1) only
D. (2) only


15. Which of the following methods can be used to reduce the speed of a spacecraft in space?
(1) Opening a parachute
(2) Firing a rocket engine at the front of the spacecraft
(3) Stretching out a pair of wings in the middle of the spacecraft (1 分)

A. (1) and (3) only
B. (1) and (2) only
C. (2) only
D. (1) only