Physics

Velocity is a vector quantity. It is the rate of change of position of an object with  period of time but in a fixed direction. - Has the same definition as speed but it has a given direction as well. Velocity = Displacement/ Time

Distance = the length of the actual path traversed by a body between its initial and final positions. Displacement = the change in the distance of an object in a fixed direction.

Speed is a scalar quantity. It is the rate of change of position(distance) of an object with time in any direction Basically speed = ds/dt Or Speed = Distance Travelled  / Time Taken Types of Speed: 1) Uniform Speed - an object is moving in uniform speed if it covers equal distances in equal periods of time. 2) Variable Speed - an object is moving in variable speed if it covers unequal distances in equal periods of time. 3) Average Speed Average Speed = Total distance traveled / Total time taken

Mass = the mass of an object / body is the amount of matter contained in it. Weight  = -The weight of a body is the force with which the Earth pulls the object towards the centre of the Earth - Weight = Mass * Gravitational Force Gravitational Force of Earth is approximately 10 meters per second squared. SI Unit of Weight is the NEWTON (N)

Volume : 1) Liquid:- using a measuring cylinder 2) Irregular Solid:- If it floats= Using a displacement can - Attach the irregular solid to a lump of metal of known volume with a string. Prepare a displacement can with water. Fill water and wait until known flows out of the spout. Put a measuring cylinder at the end of the spout. Lower the irregular solid with the lump of metal into the displacement can. The amount of water it displaces into the measuring cylinder is the volume of the irregular olid + the lump of metal. Subtract the volume of the metal with this volume. If it doesn't float= - Partly fill a measuring cylinder and record the value, lower the solid into the measuring cylinder and find out the change in the volume. Change in volume = the volume of the irregular solid. 3) Regular Solid:- Volume of rectangle = length * width * height Volume of cylinder = pi * r * r * height Volume of prism = Cross-sectional area * Height (other volume rules apply)

Volume = the amount of space an object takes up Density  = the amount of kilograms packed into every m^3 of an object. Volume  SI Unit = m^3, L, cm^3, mL Density  SI Unit = kg/ m^3, g/ cm^3 Density = Mass/ Volume - a positive scalar quantity - A mass of 1000kg of water has a volume of 1m^3 Therefore, the density of water = 1000kg/m^3 or 1g / cm^3 How can densities sometime vary? 1) Most substances  get a little bigger when heated, the increase in volume reduces their density 2) The density of gases can vary enormously on how compressed they are Important densities to remember  = Water = 1000kg/m^3 Air = 1.3 kg/m^3 Ice = 920 kg/m^3 Gold = 19300 kg/m^3 Osmium(the densest substance on Earth) = 22600 kg/m^3