physics power,energy,work

• Work is what happens when you use force to move something
• Work only works if there is movement against an opposing force.
• What is the opposing force of work?


  Friction and gravity
• Energy is the ability to do work.
• The stronger the force the greater the work
• Work is done when a force acts on an object and this force moves the object a distance in the direction of the force applied
• Work done is measured in joules or Nm
• force is measured in newtons
• distance moved is measured in meters and its symbol is S
• work is defined as the force multiplied by the distance moved in the direction of the force.
• work also depends on the vertical height
• why is more work done to pull the load up the ramp than to lift it?

  Because with the ramp you have to do work against friction and gravity
• what is chemical energy?


  Stored energy which can be released when required.
• Kinetic energy is also known as movement energy
• What is potential energy?

  It is the energy waiting to be used or released
• energy is something by which people and machines are able to work
• energy is measured in joules
• Kinetic and potential energy are types of mechanical energy
• Any object that possesses mechanical energy is able to do work
• Give me examples of elastic potential energy?

  Rubber band, stretched spring
• What type of energy does a bread store?

  chemical energy
• What type of energy is stored in a water dam?

  gravitational potential energy
• Energy can be changed from one form to another
• Energy cannot be made or destroyed
• Energy can neither be created nor destroyed but can be transferred from one form to another
• Work done= energy transferred
• What does conserved mean?

  When the energy is being transferred to a different form of energy and the amount is not changed
• To stretch the elastic of a bow we need energy. We get this energy from the food we eat so this energy is called chemical energy. This energy is changed into elastic potential energy. This stored energy in the elastic. When the elastic is released, energy is changed into kinetic energy and the arrow flies off
• The law of conservation of energy states that energy cannot be created or destroyed it can only change forms.
• The higher the object the greater the potential energy
• The heavier the object the more energy is needed in lifting it hence the greater the gravitational potential energy
• The gravitational potential energy depends on three factors, which are they?

  The objects mass, the height of the object above ground level, the gravitational pull
• The equation of gravitational potential energy is GPE=mgh
• Gravitational potential energy is measured in joules
• The height is measured in meters
• The mass of the object is measured in kilograms
• The greater its weight the greater the gravitational potential energy
• When an object is lifted upwards, its gravitational potential energy increases
• When an object falls its gravitational potential energy decreases
• The kinetic energy depends on two factors, Which are they?

  Velocity and mass