Energy and motion Flashcards
what is the difference between speed and velocity?
speed: scalar quantity with magnitude
velocity: vector quantity with magnitude and DIRECTION
formula for speed
distance/time
what does the gradient represent on a distance-time graph?
speed
what does a horizontal line represent on a distance-time graph?
stationary
formula for velocity
displacement of time
what does the gradient represent on a velocity-time graph?
acceleration
what does the area below line represent on a velocity-time graph?
total distance travelled
what does a horizontal line represent on a velocity-time graph?
constant speed
formula for acceleration and its units
change in velocity/time
unit: m/s^2
newton’s 1st law
- zero resultant force - object remain stationary
- forces are balanced: constant velocity
newton’s 2nd law
f=ma
newton’s 3rd law
for every action, there is an equal and opposite reaction
what type of quantity is momentum?
vector quantity
formula for momentum
mass x velocity
units for momentum
kg m/s
how does a large force affect momentum?
causes a fast change in momentum so greater acceleration
formula for work done
force x distance moved in direction of force
E = fd
what is difference between mass and weight?
weight is caused by pull of gravitational force so varies on each planet, mass is how much stuff in inside remains same
formula for weight
weight = mass x gravitational field strength
gravitational field strength on earth and moon
earth: 10 N/kg
moon: 1.6 N/kg
what is gravitational potential energy?
energy which occurs due to its vertical position in a gravitational field
formula for gravitational potential energy
GPE= mass x g x height GPE = mgh
formula for kinetic energy
KE= 1/2 x mass x velocity 2 KE = 1/2mv^2
