Module 3-Forces and Motion Flashcards
What is displacement and how does it differ from distance
Distance is the ground covered regardless of the direction
Whereas displacement only account for the change in position
In relation to the starting point
What do you know about displacement time graphs
Displacement goes on the y
Time goes on the x
Velocity is the gradient
What do you know about velocity time graphs
Velocity goes on y
Time goes on x
Acceleration is gradient
Displacement is area under the graph
State the SUVAT equation that beggins with v^2
v^2=u^2+2as
What is the SUVAT equation that begins in v
v=u+at
1/2(u+v)t= what
s
SUVAT equation-S is equal to what (both)
S=ut+1/2at^2
S=vt-1/2at^2
What is the equation for stopping distance
Stopping distance=thinking distance+braking distance
How does an object reach it’s terminal velocity
An object in free fall will accelerate at first as the drag is smaller than the weight
However as the object speeds up, the drag increases at the same rate
This causes the forces of drag and weight to balance out
At which point the object will stay at a constant velocity as there are no net forces to change it.
What is the equation that links force mass and acceleration
Force = mass x acceleration
What is centre of mass
Centre of mass is an imaginary point where all of the mass can be considered to be at one point
What is centre of gravity
Centre of gravity is the point directly underneath the centre of mass where the whole weight acts upon
What is drag
Drag is the force experienced on an object moving through a fluid opposite to the direction of motion
What is the equation for a moment
Moment = perpendicular force x distance to pivot
What is a couple
A couple (of torques) is a pair of rotational forces that act on the same object together spinning it without overall movement e.g. two forces on bike pedals
What is the equation for pressure
Pressure = force / area
What is the equation for density
Density = mass / volume
What is the equation for pressure of a liquid
Pressure= height (column of liquid) x density x gravitational pull
What is the equation linking work done force and distance
Work done = force x distance (in the direction of work)
What is the principle of conservation of energy
Energy cannot be created nor destroyed
What are the 8 types of energy
Kinetic
Gravitational potential
Electrical potential
Elastic potential
Chemical
Nuclear
Electromagnetic
Thermal (internal)
Define power and state equation
Power is force applied in a short time and therefore the equation is power = work done / time
What is the equation for efficiency
Efficiency = useful power output/total power input x 100%
What is a tensile and compressive force
A force that pulls an object in two opposite ways (tensile)
A force that pushes an object towards its centre (compressive)
What is the name given when an object changes shape and doesn’t return to its original form
Deformation
What is elastic potential energy
It is the energy stored up in an object when it is stretched or squashed and wants to return to its original shape
What is elastic and plastic deformation
Elastic deformation is when an object can change back to its original shape
Plastic deformation is when an object exceeds its elastic limit and cannot return to its original shape
What is the equation for tensile stress
Tensile stress=force / area
What is the equation for tensile strain
Tensile strain = extension / original length
What is young modulus
Young modulus is the gradient of the stress vs strain graph and put simply is the stiffness of a material-the higher the young modulus the stiffer the material will be
Does young modulus change with size, shape or width
None! Young modulus of an object is only dependent on the material itself
What is Newton’s first law of motion
An object will remain at rest or continue at a constant velocity as long as no resultant force acts upon it
What is Newton’s second law
The resultant force acting on an object is proportional to the rate of change of momentum
What is Newton’s third law
If object A exerts a force on object B, object B will exert an equal and opposite force on object A and the forces are the same type and in the same line of motion
What is the significance of change of momentum when relating to force
The faster the change in momentum occurs, the larger the force.
What is an impulse
An impulse is the change in momentum for example you experience a high impulse when going on a rollercoaster
What are two quantities that are conserved in all collisions
Energy
Linear momentum
What is the UTS of a material
The max amount of tensile stress it can take before it breaks
