Chunking Exercise on "Force and Movement" Direction Add spaces between letters in each letter sequence to obtain a meaningful sentence. A. 1. 2. 3. 4. 5. Effect of force Aforcecanbeapushorapull. Aforcecanstartamotion. Aforcecanchangethespeedofabody. Aforcecanchangethedirectionofamovingbody. Forcescanchangetheshapeofabody. B. Measuring force 1. Theunitofforceisnewton. 2. 3. Aspringbalanceisusedtomeasureforce. Theextensionofaspringisproportionaltotheforceonit. C. Friction 1. Frictionopposesmotion. 2. Abodymovinginafluidexperiencesafrictionalforceduetothefluid. 3. Thefrictioninwaterislargerthanthatinair. 4. 5. 6. Ahovercraftusesairtoreducefriction. Lubricantsandrollersareusedtoreducefriction. Astreamlinedbodyexperienceslessfrictioninafluid. D. 1. 2. 3. 4. Mass and weight Gravitationalforceactsfromadistance. Theweightofabodyistheforceofgravityactingonthebody. Massisameasureofinertia. Theweightofabodydependsonitsposition. 5. Theunitofmassiskilogram. E. 1. 2. 3. 4. 5. Lever and pulley Momentistheturningeffectofaforce. Momentisforcetimesdistancefromtheturningcentre. Themomentonbothsidescanceloneanotherinabalancedlever. Pulleysandleversaresimplemachines. Usingamachine,wecanuseasmalleffortotmovealargeload. 6. Theelbowjointandtheanklejointareleversystemsinthehumanbody. F. 1. 2. Action and reaction Forcesexertinpairsbetweentwobodies. Actionandreactionareequalbutopposite. G. Work and energy 1. Workdoneisenergytransformationinvolvingforceandmovement. 2. Workequalsforcetimesdistancemoved. 3. Theunitofworkisjoule. Key A. 6. 7. 8. 9. 10. Effect of force A force can be a push or a pull. A force can start a motion. A force can change the speed of a body. A force can change the direction of a moving body. Forces can change the shape of a body. B. Measuring force 4. The unit of force is newton. 5. A spring balance is used to measure force. 6. The extension of a spring is proportional to the force on it. C. 7. 8. 9. 10. 11. 12. Friction Friction opposes motion. A body moving in a fluid experiences a frictional force due to the fluid. The friction in water is larger than that in air. A hovercraft uses air to reduce friction. Lubricants and rollers are used to reduce friction. A streamlined body experiences less friction in a fluid. D. 6. 7. 8. 9. 10. Mass and weight Gravitational force acts from a distance. The weight of a body is the force of gravity acting on the body. Mass is a measure of inertia. The weight of a body depends on its position. The unit of mass is kilogram. E. Lever and pulley 7. Moment is the turning effect of a force. 8. 9. 10. 11. 12. Moment is force times distance from the turning centre. The moment on both sides cancel one another in a balanced lever. Pulleys and levers are simple machines. Using a machine, we can use a small effort ot move a large load. The elbow joint and the ankle joint are lever systems in the human body. F. 3. Action and reaction Forces exert in pairs between two bodies. 4. Action and reaction are equal but opposite. G. Work and energy 4. Work done is energy transformation involving force and movement. 5. Work equals force times distance moved. 6. The unit of work is joule.