Physics

Physics

1. Types of Waves

   • Transverse waves
     • Waves on the surface of the water are transverse waves. Particles in the water move up and down as a wave passes - the particle are not carried to the shore
   • Longitudinal waves
     • Sound waves also transfer energy. Sound waves are longitudinal waves. Particles in the material through which the wave is travelling move backward and forwards as the waves passes.

2. Calculating formulas:

   • Kinetic energy
     • Kinetic energy is when energy is stored in moving objects, The amount of kinetic energy stored in a moving object depends on its mass and its speed
   • Potential energy
     • Potential energy is energy that is stored because of an object position in a gravitational field everytime something is moved upwards it stores more potential energy
     • On Earth we always have the force of gravity acting upon us When we're above the Earth's surface we have potential (stored) energy . this is called gravitational potential energy. The amount of gravitational potential energy an object on Earth has depends on it's -mass and -height above the ground
   • Acceleration equations
     • When an object moves in a straight line with a constant acceleration, you can calculate its acceleration if you know how much its velocity changes and how long this takes
   • Newtons second law of motion states that objects with balanced forces acting on them will stay at rest in constant motion
     • F=ma
     • The direction of the objects acceleration is the same as the direction of the unbalanced force
       • The magnitude of the objects acceleration varies in direct proportion with the size of the unbalanced force
         • The magnitude of the objects acceleration varies inversely with the mass of the object
           • the unit of force is called the newton (N)

3. Velocity-Time Graph

   • Velocity-time graph are used for objects moving with a constant velocity or constant acceleration
     • The Velocity of an object is its speed in a particular direction. this means that two cars will have different velocities if they are travelling at
       • The same speed but in different directions
         • the different speeds in the same direction
           • The different speeds in different directions
       • The vertical axis of a velocity-time graph is the velocity of the object. The horizontal axis is the same from the start

4. Distance-time graphs

   • You should be able to draw and explain distance-time graphs for a stationary object or an object moving at a steady speed in a straight line
     • The vertical axis of distance-time graph is the distance travelled from the start from the start. The horizontal axis is the time from the start
       • Calculating speed

5. Calculating the mean

   • How to calculate the mean is by adding up all the numbers you have and diving by the amount of numbers you have and by doing this it will give you the mean

6. Calculating the gradient from a graph

   • Finding gradient
     • The gradient of a line on a velocity-time graph represents the acceleration of the object.
     • To work out the area of the light blue triangle on the velocity-time graph, you use the equation area of triangle = 1/2 x base x height. looking at the graph you can see that the width is 4 seconds and the height is 8 meters per seconds, so you put it in the equation =1/2x8x4 =32 divided by a half which gives the final answer of =16m
     • To work out the area of the dark-blue rectangle, because it is a rectangle the equation would be height x width and looking at the graph the width of the rectangle is 6 seconds and the height is 8 meters per seconds. So it would be =8 x 6= 48 m
     • To work out the area of the whole graph what you would do is light blue triangle which is 16m + dark blue rectangle which is 48 m = which gives you a answer of 64m this hsows the distanced covered
   • finding the gradient of straight line
     • An example of finding the gradient of straight line would be :

7. Refraction

   • Waves can change direction when they move into a different medium. the change in direction is called refraction and happens at the interface (Boundary) between the two media. A line at right angles to the interface is called the normal line. We can see things when light refracted from them reaches our eyes. for example, an object on the bottom of a swimming pool looks closer than it really is because light reflected by it changes direction when it leaves the water
   • Reflected - the wave 'bounces' off
     • Refracted - the wave which passes through the material but changes the directions in which it is travelling
       • Transmitted - the wave passes through the material and is not absorbed or reflected
         • Absorbed - The wave disappears as the energy it is carrying is transferred to the material

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