MODULE 2

FORCES AND PRESSURE

CHAPTER 3FORCES AND PRESSURE

1. It is very difficult to walk on a sandy beach when wearing high-heeled shoes. This is becauseA the pressure acting on the sandy ground is too largeB the force acting on the sandy ground is too largeC the area of the sole of each shoe is too largeD the person is pressing too hard on the sandy ground

2 Which of the following factors will not affect the pressure in a liquid?A Gravitational field strength B Density of the liquid C Volume of the liquid D Depth of the liquid

3 Which of the following graphs represents the relationship between the pressure, P, and the depth, h, of a column of water?

4 When a balloon filled with helium is sealed and released in the air,A the balloon drops lower and decreases in sizeB the balloon rises and increases in sizeC the balloon stays at the same height but decreases in sizeD the balloon drops lower but increases in size

5 A barometer as shown in the figure is carried to the top of a mountain from a beach.

HOW would the atmospheric pressure and the length ℓ vary?

Atmospheric Pressure Length, ℓ

A Increases Increases

B Decreases Increases

C Increases Decreases

D Decreases Decreases

6 The figure shows a U-tube manometer used to measure the pressure of a gas supply.

What is the difference in pressure between the gas supply and the atmospheric pressure?A 3 cm of waterB 15 cm of water C 17 cm of water D 18 cm of water

7 A bowl of hot soup covered with an airtight lid is left to cool as shown in the figure.

Why is it difficult to open the lid when the soup is cold?A Water vapour cannot escape and condenses on the lidB The atmospheric pressure is greater than the air pressure in the bowlC The air molecules move faster than the water moleculesD The airtight lid prevents the air molecules to decrease in size when the soup gets cold

8 The figure shows a hydraulic pump.

If the force applied is 10 N, what is the weight of the load that can be lifted?A 500 NB 1000 NC 2000 ND 5000 N

9 A mechanic notices some air bubbles in the hydraulic brake fluid of a car. He recommends changing the brake fluid. This is because

A the air bubbles will easily be compressed by pressure and affects the transmission of pressure

B the air bubbles will escape from the piston and cause the brake fluid to leakC the air bubbles will expand when they are heated up and cause an explosionD the air bubbles will increase in size and cause the brake fluid to be incompressible

10 A light cylindrical wooden block is dropped vertically into a basin of water as shown below.

Which of the following would happen?

A The wooden block will stay afloat horizontallyB The wooden block will stay afloat verticallyC The wooden block will sink vertically to the bottomD The wooden block will stay afloat vertically but fully immersed in the water

11 An inverted test tube with some air trapped in it is placed in a tank as shown in the figure.

When the piston is pushed inwards, the test tube A moves to the left B moves to the right C rises higher D sinks lower

12 The figure shows the cross section of an aerofoil.

If the aerofoil moves in the direction P, which of the following is true about the speed of the air flow and the pressure of the air at point X?

13 A metal sheet has mass of 0.5 kg and area of 0.8 m . What is the pressure of the metal sheet acting on a surface? A 4.15 Pa B 5.45 Pa C 6.25 Pa D 7.55 Pa E 8.85 Pa

14

The figure above shows a block of gold with uniform cross sectional area ABCDE placed on the surface of a floor. If the block of gold can be placed in a stable state of any of its surface, which of the following will produce maximum pressure on the floor?

A ABCDE C CDIH B BCHG D DEJI

15 For a pin to enter a wooden board, the pressure exerted must be greater than 5 x 107 Pa. If the pin point has an area of 0.02 mm2, find the minimum force for the pin to enter the board.A 1N D 4N B 2N E 5N

16 Gas is trapped in a closed container. There is gas pressure inside the container because gas moleculesA move randomlyB move with equal speedC collide constantly with the walls of the containerD collide with one another

17 What will happen to the kinetic energy of gas molecules when they collide elastically?A Increases B Decreases

Speed of air flow Pressure of air

A Low High

B Low Low

C High Low

D High High

B

C Remains constant D Becomes zero

18

The figure above shows a mercury column in a glass tube with trapped air in it. If the height of the mercury column is 24 cm and atmospheric pressure is 76 cm Hg, what is the pressure of the column in the glass tube? A 42 cm Hg B 52 cm Hg C 82 cm Hg D 1000 cm Hg E 120 cm Hg

19 Based on the kinetic theory of gases, the pressure exerted by a gas is caused byA collision of the gas molecules with the walls of a containerB gas molecules colliding with each other at high speedC random motion of the gas moleculesD gas molecules being very far apart from each other

20.Which of the following instruments is meant for measuring atmospheric pressure?A CarburetorB SiphonC Fortin's barometer D Hydrometer

21

The figure above shows a hydraulic jack. The cross sectional areas of smaller piston and larger piston are 20 cm2 and 60 cm2 respectively. If the smaller piston is pushed with a force of 15 N, what will be the force experienced by the larger piston?A 30N D 50N B 40N E 55N C 45N

22 Which of the following is not an application of Pascal's principle?A Hydraulic jackB Braking system of a vehicle C ManometerD Water bed

23

The figure above shows a man blowing hard at the opening of a metal tube. It is observed that the polystyrene sphere is lifted to the opening of the metal tube. This phenomenon occurs becauseA the air velocity at the upper section of the metal tube is less than the air velocity at the

lower section B the air pressure at the upper section of the metal tube is less than the air pressure at

the lower sectionC the air density at the upper section of the metal tube is more than the air density at the

lower sectionD the air temperature at the upper section of the metal tube is more than the air

temperature at the lower section

24 Which of the following is based on Bernoulli's principle?A Bourdon gauge B Insect spray C Lift pumpD Siphon

25

Air flows through a horizontal tube as shown in the figure causing water columns to rise in three vertical glass tubes. Which of the regions A, B or C has the highest air velocity?