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physics exam revision - Coggle Diagram

- - - - magnetic is the energy stored when repelling poles have been pushed closer together or when attracting poles have been pulled further apart.
      - internal is the total kinetic and potential energy of the particles in an object. In most cases this is the vibrations - also known as the kinetic energy - of particles. In hotter objects, the particles will vibrate faster and store more internal energy.
      - chemical is the energy stored in chemical bonds, such as those between molecules.
      - kinetic is the energy of a moving object.
      - electro elastic is the energy stored when repelling charges have been moved closer together or when attracting charges have been pulled further apart.
      - elastic potential is the energy stored when an object is stretched or squashed
      - gravitational potential is the energy of an object at height
      - nuclear is the energy stored in the nucleus of an atom
  - - - type of transfers
        
        mechanical work - a force moving an object through a distance
        
        electrical work - charges moving due to a potential difference
        
        heating - due to temperature difference caused electrically or by chemical reaction
        
        radiation - energy transferred as a wave, eg light and infrared - the Sun emits light radiation and infrared radiation
  - - - kinetic energy calculation
        
        [\ E_{k} = 1.8 \ J ]
        
        [\ E_{k} = \frac{1}{2} \times 0.1 \times 36 ]
        
        [\ E_{k} = \frac{1}{2} \times 0.1 \times 6^{2} ]
        
        [\ E_{k} = \frac{1}{2} \times mv^{2} ]
        
        An apple of mass 100 g falls from a tree. It reaches a speed of 6 m/s before landing on Isaac's head. What is the gain of kinetic energy of the apple?
      - EXAMPLE!
    - - The amount of elastic potential energy stored in a stretched spring can be calculated using the equation:
        Elastic potential energy = × spring constant × extension2
        
        EXAMPLE!
        
        Robert stretches a spring with a spring constant of 3 N/m until it is extended by 50 cm. What is the elastic potential energy stored by the spring?
        
        [\ E_{e} = \frac{1}{2} \times kx^{2} ]
        
        [\ E_{e} = \frac{1}{2} \times 3 \times 0.5^{2} ]
        
        [\ E_{e} = \frac{1}{2} \times 3 \times 0.25 ]
        
        [\ E_{e} = 0.375 \ J ]
    - - The amount of gravitational potential energy stored by an object at height can be calculated using the equation:
        gravitational potential energy = mass × gravitational field strength × height
        
        EXAMPLE!
        
        Galileo takes a 5 kg cannonball to the top of the Tower of Pisa for one of his experiments. The tower is 56 m high. How much gravitational potential energy has the cannonball gained? (g = 10 N/kg)
        
        [\ E_{p} = m \ g \ h ]
        
        [\ E_{p} = 5 \times 10 \times 56 ]
        
        [\ E_{p} = 2,800 \ J ]
    - - Calculating work done by a force
      - The amount of work done when a force acts on a body depends on two things:
      - the size of the force acting on the object
      - the distance through which the force causes the body to move in the direction of the force
      - The equation used to calculate the work done is:
      - work done = force × distance
- - - - Use a ruler to measure the length (l), width (w) and height (h) of a steel cube.
      - Place the steel cube on the top pan balance and measure its mass.
      - Calculate the volume of the cube using (l × w × h).
      - Use the measurements to calculate the density of the metal.
      - Use vernier callipers to measure the diameter of the sphere.
      - Place the metal sphere on the top pan balance and measure its mass.
      - Calculate the volume of the sphere using
      - Use the measurements to calculate the density of the metal.
      - Method 2: Stone or other irregular shaped object
      - Place the stone on the top pan balance and measure its mass.
      - Fill the displacement can until the water is level with the bottom of the pipe.
      - Place a measuring cylinder under the pipe ready to collect the displaced water.
      - Carefully drop the stone into the can and wait until no more water runs into the cylinder.
      - Measure the volume of the displaced water.
      - Use the measurements to calculate the density of the stone.
      - Method 3: Water (or any liquid)
      - Place the measuring cylinder on the top pan balance and measure its mass.
      - Pour 50 cm3 of water into the measuring cylinder and measure its new mass.
      - Subtract the mass in step 1 from the mass in step 2. This is the mass of 50 cm3 of water.
      - Use the measurements to calculate the density of the water.
    - - All matter contains particles. The difference between the different states of matter is how the particles are arranged:
      - in a solid - particles are tightly packed in a regular structure
      - in a liquid - particles are tightly packed but free to move past each other
      - in a gas - particles are spread out and move randomly