Physics- Mechanics

• A force is anything that can change the motion of an object
• The acceleration always acts in the same direction as the net force
• A vector is a physical quantity with two properties: size and direction
• For vector addition, arrange the vectors so the tail of the 2nd vector is at the tip of the first. Then, draw an arrow from the tail of the 1st vector to the tip of the second to find the resultant vector.
• Fsupport acts perpendicular to the surface
• For vector subtraction, flip the initial vector then add the final. The change in vector will be from the tail of the flipped initial to the tip of the final
• For relative velocity, flip the velocity vector of the observer, and add it to the other object's velocity vector. Tail to tip is the relative velocity to the observer.
• Velocity is measured in ms^-1
• An object that is in the air (and therefore only under the influence of gravity) is a projectile. Regardless of its velocity, it is always accelerating downwards at 9.8ms^-1/
• Any object that is following a circular path is undergoing circular motion. At any instant, the objects velocity is at a tangent to its path. There is a net force that acts towards the centre of the circle- this acts as a centripetal force.
• If a centripetal force acts on an object it will create a centripetal acceleration in the same direction.
• A torque is a turning force that causes an object to rotate around a pivot point.
• Equilibrium is a state in a system where forces up = forces down and torques clockwise = torques anti-clockwise
• Torque is measured in Nm
• Energy is the ability to do work/exert a force to displace an object.
• Kinetic energy is the energy of a moving object
• Gravitational potential energy is energy stored in an object held above the ground
• Elastic potential energy is energy stored in a stretched/compressed spring (or other)
• Energy cannot be created or destroyed, but is transformed from one type to another.
• Momentum is a vector quantity, representing the motion of a mass.
• Momentum is measured in kgms^-1
• Impulse is a concept that describes the relationship between momentum, force and time
• For a given change in momentum, the peak force acting on an object to create the change in P can be altered by the time across which the force is applied to change the P
• Work is the transfer of energy from on form to another
• Work is measured in Joules
• Power is the rate at which energy is transformed
• Power is measured in Watts
• Newton's 1st Law: An object maintains constant velocity unless acted upon by an external force
• Newton's 2nd Law: If an object experiences an external net force, it will accelerate such that F=ma
• Newton's 3rd Law: When an object exerts force on another object, the second object will simultaneously exert a force of the same size and opposite direction to the force acting upon it (any action force has an equal and opposite reaction force)
• micro =10^-6 = $\mu$
• milli = 10^-3 =m
• centi = 1/100 = c
• kilo = 10^3 = k
• mega = 10^6 = M