energy Flashcards
(23 cards)
what is kinetic energy
the energy stored in moving objects
equation for kinetic energy
0.5 x mass x speed squared
what is kinetic energy measured in
joules
unit for mass
kg
unit for speed
m/s
what type of objects have no kinetic energy
stationary objects
a tennis ball is travelling at 50 m/s
has kinetic energy of 75 j
what is mass of the ball
Ke = 1/2 m x v squared
m=2ke/v squared
m= 2(75)/50 squared
= 0.06
what is the energy change in a car running at a constant speed
chemical energy——> kinetic energy
what are we doing when stretching a spring
applying a force to change the length of a spring
what is applying a force called
work
what is elastic potential energy
the energy stored in a stretched spring
symbol for extension
lower case e
describe graph for extension of spring against force applied
straight line passing through 0
what happens if we apply to great of a force on a spring
the extension is no longer proportional to the force
what happens when a spring is stretched beyond the limit of proportionality
it will not return to original length if we remove force
what is limit of proportionality
the point at which the extension is no longer proportional to the force
what energy store does a stretched spring have
elastic potential energy
what is spring constant measured in
N/m
unit for extension
m
symbol for spring constant
k
what does the value of the spring constant depend on
the spring
define gravitational potential energy
energy stored in an object due to its position above the earths surface
what is gravitational potential energy due to
the force of energy acting on an object
