# CXC Integrated Science exam guide: Section D: Forces

CXC Integrated Science exam guide: Forces

CXC Integrated Science Exam Guide

Section D- Transportation

General objectives of the section:

Candidates should demonstrate an understanding of:

 1 The basic principals involved in motion on land and in water and flight through air and space; 2 The scientific principals of road safety practices; 3 The nature of the gravitational force; 4 The motions taking place within our solar system ; . 5 The characteristics of space; 6 Earth and air movements and their effects ; 7 The principals of conservation of mass energy and momentum; 8 The methods used in transferring energy.

 UNIT II - FORCES Specific Objectives Students should be able to: Explanatory notes Suggested Practical Activities 1 Discuss the principles of forces; Action/reaction principle applied in space transport; the forward motion of jet aircraft; relationship between shape of wings of planes and birds and lift forces they experience while moving through the air; motion of vehicles, road surfaces and tyres; the effects of wind speed and wind currents on the motion of aircraft Action-reaction principles, for example, releasing an inflated balloon, using a pair of spring balances; demonstrate by blowing over strips of paper held at one end; use of ball on different surfaces; use of paper aircraft models and fan) 2 describe gravity as a force; Definition, centripetal and centrifugal forces; the relationship between height of the center of gravity of an object and its stability;  the implications for stability on the loading of vehicles in relation to their center of gravity; reasons for maximum loading capacity and tare Show how an object can escape the pull of gravity; throwing a ball up and observing its motion; releasing objects attached to suspended spring/ not attached to anything; using models to demonstrate how an object can escape the pull of gravity if given enough kinetic energy by whirling around the head of a rubber band attached to a weak thread 3 define center of gravity Conditions for equilibrium under parallel forces; Use of cardboard cut-outs of triangles, rectangles, circles and irregular shapes to arrive at the approximate position of the center of gravity of objects of simple shapes; items such as lead pencils, rulers and solids with regular shapes should be used to locate the center of gravity. 4 define stable and unstable and neutral equilibrium; The characteristics of space and how problems affecting human life in space might be overcome. Use of small ball, a concave/convex dish, or a cone shaped object and a flat surface to demonstrate the three types of equilibrium; use of  rule suspended by a spring balance and kept horizontal by known suspended weights to show that: the sum of the forces in one direction must equal the sum in the opposite direction the sum of the clockwise moments about a pivot must equal the sum of anti-clockwise movements 5. explain the term “satellite” Use of models to show how the planets orbit the sun

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