Basic Electrical Installation Work

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