Basic Electrical Installation Work

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● ‘Magnetic force’is the force created magnetic field. ● ‘Magnetic force’ the force created magnetic field. kN/m2 These two examples show that the young woman exerts times more pressure the ground than the elephant. Calculate the pressure exerted the shoe the floor (assuming the acceleration due gravity 9. ● ‘Gravitational force’is the force acting towards the centre the earth due the effect gravity. Pressure Force Area (N/m ) Pressure kg m/s m 2 2 4 2 1000 81 400 10 .Basic electrotechnical units and theory 87 ● ‘Shearing force’ the force which moves one face material over another. ● ‘Compressive force’is the force pushing things together. ● ‘Centrifugal force’is the force acting away from the centre, the opposite centripetal force. ● ‘Friction force’is the force which resists prevents the movement of two surfaces contact. ● ‘Gravitational force’ the force acting towards the centre the earth due the effect gravity. Pressure stress measure of the force per unit area. 6 6 2 kN/m Example 2 A small circus elephant mass tonne (1000kg) puts all its weight one foot which has a surface area 400cm2 . Definition Pressure stress measure the force per unit area.81m/s2 . Work done Suppose broken-down motor car was pushed along road, work would done the car applying the force necessary move along the road.81m/s2 ). Calculate the pressure exerted the elephant’s foot the floor, assuming the acceleration due gravity 9. ● ‘Tensile force’is the force pulling things apart. Pressure stress Force Area N/m ) 2 Example 1 A young woman mass 60kg puts all her weight the heel one shoe which has an area 1cm2 . Heavy breathing and perspiration would evidence the work done. Pressure stress To move broken-down motor car might exert force the back the car propel forward. ● ‘Electrical force’is the force created by electrical field. ● ‘Centripetal force’is the force acting towards the centre when a mass attached string is rotated circular path. hands would apply pressure the body panel the point contact with the car. This because her mass exerts force over much smaller area than the elephant’s foot and the reason why many wooden dance floors are damaged by high-heeled shoes. . ● ‘Shearing force’is the force which moves one face material over another. ● ‘Centripetal force’ the force acting towards the centre when mass attached string rotated circular path. Definition ● ‘Inertial force’is the force required to get things moving, change direction stop, like the motor car discussed above. ● ‘Centrifugal force’ the force acting away from the centre, the oppo- site centripetal force. 245 3 . ● ‘Cohesive adhesive force’is the force required hold things together. Pressure Force Area (N/m ) Pressure kg m/s m 2 2 4 2 60 81 1 10 588 . ● ‘Electrical force’ the force created electrical field