module 3 - physics

• free fall is only gravity
• the gradient of a displacement time graph is the velocity
• on a d-t graph a larger acceleration will have a steeper gradient
• on a d-t graph a smaller acceleration will have a less steep gradient
• on a d-t graph deceleration will have a decreasing gradient
• on a v-t graph the gradient is the acceleration
• on a v-t graph the area under the graph is the displacement
• on a v-t graph is the line is curved it means non-uniform acceleration
• a net force is needed for the object to accelerate
• if forces are balanced they're in equilibrium
• most common forces

  • weight
  • normal contact
  • tension
  • friction
• the acceleration of an object is directly proportional to the force applied
• $F=$$MA$ is newtons second law
• all objects fall at the same rate if you ignore air resistance
• To work out the horizontal component of a force you use Fh=fcos0
• to work out the vertical component of a force you use Fv=Fsin0
• the equation for weight is $W=$$mg$
• friction is a force that opposes motion
• terminal velocity is when the friction = driving force
• constant friction is between two surfaces
• fluid friction is drag or air resistance
• density is the mass per unit volume and the equation for it is$\rho=$$m/v$
• pressure is the force per unit are and the equation is either p=h(density)g or $p=$$f/a$
• upthrusts equal to the weight
• a moment is the turning effect of a force
• the equation for moments is M=FD
• A couple is a pair of forces that don't cause any resultant linear force but does produce a turning force (usually called a torque)
• the equation for a torque is T=FD
• work is done when energy is transferred
• the equation for work is $W=$$Fx$
• work is the energy that's been changed from one form to another
• power is the work done per second
• the equation for power is either P=W/T or P=FV
• Power is measured in watts
• work done is measured in joules
• energy is measured in joules
• density is measured in kg/m3
• pressure is measured in pascals
• kinetic energy is the energy an object has when its moving
• the equation for kinetic energy is Ek=1/2mv^2