ESSAYS QUESTIONS

FORM 4

CHAPTER: FORCES AND MOTION

QUESTION 1

IMPROVING PERFORMANCE IN POLE VAULTER

(LOMPAT TINGGI)

modification	explanation
Vaulter attire The attire must be thigh and light	Less air resistance and the athlete can accelerate more and increase his momentum when he jump
Pole The pole use must be elastic and strong	Increase the elastic potential energy in the pole. The stored elastic potential energy  will be converted into gravitional potential energy to the athlete The pole not break easily
Thick mattress	Reduce impulsive force and increased time of impact
Spike shoes	Decrease friction

QUESTION 6

DESIGN A RADIO CONTROLLER HELICOPTER

Modifications	Explanation
Reaction time The reaction time should be short as possible	Helicopter can respond to the command quickly
Mass The mass should be small	Can accelerate faster and easier to turn around or stop
Rate of fuel consumption The rate must be high	Produce greater propulsive force
Body shape should be streamlined or aerodynamic	Reduce friction during its flight
Material Used The material for the body should be strong	Resist damage during any collision

QUESTION 2

FEATURED TO BE INSTALLED IN SATELITE

Modification	Explanation
Material Satellite must be made up of material with melting point	Does not melt easily when it reaches high temperature due to air friction with atmospheric air
Shape The satellite is designed with streamlined shape which gradually tappers towards the end	Decrease the air resistance
Shelter Satellite is sheltered with insulators tile	Prevent heat from entering
Satellite is made up of composite material which is light, hard ,strong	Not easily broken into pieces when landing
Satellite is equipped with parachute	Descend slowly and decreased it velocity during landing
Satellite made up of material which can reduce impulsive force	Increased the impact time and prevent the satellite from broken

QUESTION 4

MODIFICATION OF THE DAM

Modification	Explanation
Wall are thicker at the bottom	Withstand water pressure. Water increase with depth
Area of the base increased	Reduce pressure at the base
Wall are constructed using stronger materials by  adding steel or concrete	resist stretching, bending and other tensile actions
wall are coated with waterproof material	Waterproof materials stop water from leaking from the wall
Equipped with water overflow system	Allow water to chanelled away when the volume of water increased the limits

QUESTION 3

MODIFICATION FOR HYDRAULIC  FLUID  SYSTEM

Modifications	Explanation
Used hydraulic fluid of lower density	Hydraulic fluid is light and can flow more easily
Hydraulic fluid has high melting points	Hydraulic fluid does not boiling and vaporize easily
Used hydraulic fliud with low compressibility	Provide sharp pedal feel and instant response because little force is wasted in compressing the fluid
Ratio of the cross sectional area to piston to that of brake piston should be large as possible	A larger force can be applied on the brake

QUESTION 5

MODIFICATION FOR COOKING APPARATUS

Modification	Explanation
Base of the pot must be made of material with low heat specific capacity such as copper	Copper has lower heat capacity. The pot will become hot faster, so the food can be cooked faster
The body of cooking utensil does not oxidized easily	Pot is durable and will not contaminate with dangerous material
Handles made of composite material of high specific heat capacity are added	The handle does not become too hot when cooking
Fitted with lid	Prevent heat loss to the surrounding and the food cook up faster
Body of the cooking utensil made up of aluminium	The low density of aliminuim reduce the overall weight ,make the pot more durable

QUESTION 7

MODIFICATIONS OF RAFT

Modifications	Explanation
Used dry bamboo as the material	Have low density and light
Used bamboo with bigger diameter and thin wall	Have low density
The bamboo tightened together closely	Produces greater surfaces
The shape must be streamlined	Reduces water friction
The bamboo are arranged in more than one layer	Accommodate more weight

QUESTION 8

MODIFICATION OF THERMOMETER

Modification	Explanation
Has thinned walled glass	Improved sensitivity of the thermometer
Small diameter of capillary tube	small expansion of mercury in the thermometer caused a big change in the length of mercury thread
Has thick wall of glass bore	Reduce heat lost to the surrounding
Has round shape of the glass bore stem	Provide small surface and reduce the heat lost to the surrounding
The material inside the thermometer must be opaque (legap)	Easy to take the reading