p2 forces Flashcards
define a scalar quantity
a quantity which has size (magnitude) only
what is the equation for speed
speed = distance / time
give three examples of scalar quantities
speed
distance
time
define a vector quantity
a quantity with both size (magnitude) and direction
define velocity
speed in a particular direction
define displacement
the distance moved in a particular direction
what is the equation for velocity
velocity = displacement / time
define acceleration
the rate of change of velocity
what is the equation for acceleration
acceleration = change in velocity (m/s) / time (s)
what is acceleration measured in
m/s**2
what is the unit for forces
Newtons (N)
when do forces occur
when there is an interaction between two objects
list all the contact forces
friction
air resistance (drag)
upthrust
lift
tension
normal contact
list all the non contact forces
gravitational (weight)
magnetic
electrostatic
define a balanced force
two equal forces in opposite directions (constant speed)
define an unbalanced force
when the force in one direction is greater than the force in the opposite direction
define kinetic energy
the energy of a moving object
what is the equation for kinetic energy
kinetic energy (j) = 1/2 x mass (kg) x velocity**2 (m/s)
define gravitational potential energy
energy stored by something above the earths surface
what is the calculation for gravitational potential energy
gpe (j) = mass (kg) x gravitational feild strength (N/kg) x height (m)
what is the gravitational field strength on earth
10N/kg
what does suvat stand for
s = displacement (m)
u = initial velocity (m/s)
v = final velocity (m/s)
a = acceleration (m/s**2)
t = time (s)
what are the three suvat equations
v = u + at
s = 1/2 (u+v) t
v2 = u2 + 2as
