C8

Question 1

Force

Answer 1

Pull or push upon an object

Question 2

Effects of force

Answer 2

Cannot be seen but can be felt or observed

Question 3

G f

Answer 3

Force of attraction between masses

Question 4

N f

Answer 4

Force acting perpendicular to the surfaces of objects in contact

Question 5

F f

Answer 5

Force that opposes motion when two surfaces rub against one another

Question 6

E f

Answer 6

force produced when an object is stretched or compressed

Question 7

B f

Answer 7

force that pushes an object upwards in a fluid

Question 8

Ec f

Answer 8

Force of attraction or repulsion between electrostatic charges

Question 9

M f

Answer 9

force of attraction or repulsion in a magnetic field

Question 10

Magnitude of force is measured

Answer 10

Spring balance

Question 11

Floating

Answer 11

Buoyant force > weight, object is less dense than the liquid

Question 12

Submerging

Answer 12

Buoyant force < weight, object is denser than the liquid

Question 13

First class lever

Answer 13

When the fulcrum is nearer to the load, a small effort can carry a large load.
When the fulcrum is nearer to the effort, a small movement can produce a large movement.

Question 14

Second class lever

Answer 14

When the effort is further from the fulcrum, a small effort can carry a large load.

Question 15

Third class lever

Answer 15

When the effort is nearer to the fulcrum, a large effort is needed to carry a small load.

Question 16

FCL eg

Answer 16

Hammer, scissors

Question 17

SCL eg

Answer 17

Bottle opener, wheelbarrow

Question 18

TCL eg

Answer 18

Stapler, broom

Question 19

Formula for solving lever problems

Answer 19

Exd= Lxd

Question 20

Formula for moment of force

Answer 20

M(nm)=fxd

Question 21

Formula for pressure

Answer 21

P=f/a

Question 22

Si unit for pressure

Answer 22

N m -square

Question 23

Hypothesis for pressure

Answer 23

The smaller the surface area, the larger the pressure

Question 24

Assume that gas particles are represented by footballs and the wall of a container is represented by a wall.

Answer 24

When the footballs hit the wall, pressure will be exerted by the footballs on the wall. A similar situation occurs in the collision of gas particles with wall of a container that will produce gas pressure.

Question 25

Factors that affects air pressure

Answer 25

Volume, Temperature

Question 26

Volume ap

Answer 26

When the volume of air reduced, its air pressure will increase

Question 27

Temperature ap

Answer 27

air pressure increases with the increase in its temperature.

Question 28

Air pressure

Answer 28

Collisions between gas particles in the air and the wall of a container

Question 29

Atmospheric pressure

Answer 29

collision of gas particles in the atmosphere with certain bodies.

Question 30

Atmospheric pressure depends on

Answer 30

Height above sea level

Question 31

Hypothesis for atmospheric pressure

Answer 31

Atmospheric pressure decreases as the height above sea level increases

Question 32

Areas that has more gas particles

Answer 32

Near to sea level

Question 33

Magdeburg hemispheres

Answer 33

When the air trapped in the hemispheres is pumped out, the space within the hemispheres forms a vacuum. On the outside of the hemispheres, the atmospheric pressure exerts a huge force on the outer surface of the hemispheres that keeps both hemispheres (tightly) together. Both hemispheres cannot be separated even by using a large force. The pressure inside the hemispheres becomes very low.

Question 34

Drinking straw

Answer 34

When one end of the drinking straw is sucked, the air inside the drinking straw is removed.This action causes the air pressure in the drinking straw to decrease and become lower than atmospheric pressure.The higher atmospheric pressure on the surface of the liquid pushes the liquid into the drinking straw and then up into the mouth through the drinking straw.

Question 35

Plunger

Answer 35

A plunger is pressed down to drive out the air underneath the rubber cup, X. The volume of air in X is reduced. As the plunger is pulled upwards, the volume of air in X increases while the air pressure in X becomes lower than air pressure in Y. The higher air pressure in the space Y in the drainage pipe will push and break up the blockage

Question 36

Siphon

Answer 36

A siphon is a tube completely filled with liquid. When the liquid in a siphon flows out of its lower end, the pressure of the liquid at this lower end of the siphon is reduced. Atmospheric pressure on the surface of the liquid in the container in the higher position will push the liquid into the upper end of the siphon. As a result, this causes a continuous flow of liquid through the siphon from the upper end to the lower end.

Question 37

Syringe

Answer 37

When piston is pulled upwards, the volume of air in the space below the piston increases while its air pressure decreases.The higher atmospheric pressure pushes the liquid up into the syringe through the hole of its needle.

Question 38

Vacuum cleaner

Answer 38

When the electric fan is turned on and is rotating, some of the air in space X is sucked out through an opening. The reduced amount of air lowers the air pressure in space X. As a result, the outside air pressure which is higher causes air to be sucked into the vacuum cleaner.

Question 39

Hypothesis for liquid pressure

Answer 39

Liquid pressure increases as the depth in a liquid increases

Question 40

Effect is shown by for lp

Answer 40

volume of an air bubble which increases when its depth in water decreases

Question 41

Design of a submarine

Answer 41

has a thick steel wall that can withstand the increase in water pressure in depths of water.

Question 42

Thickness of walls of a dam

Answer 42

As water pressure increases with depth, a thicker wall is built at the base of a dam to withstand the higher water pressure