chapter 9 test Flashcards
what is conserved?
mechanical energy is conserved when there is no net work done by external forces
Kinetic energy equation
KE= 1/2 mv^2
Gravitational Potential Energy equation
PE = mgh
Spring potential energy equation
PE = 1/2 kx^2
What does the term mechanical energy refer to?
the sum of a systems kinetic and potential energy
positive work is…
is done by a force PARALLEL to an objects displacement
negative work is …
is done by a force ANTIPARALLEL to an objects displacement
when a force is acting perpendicular to an object displacement …
no work is done
what type of quantity is work?
scalar because it can be positive or negative but it does not have a direction
in a force vs. displacement graph what is the work?
the area underneath the graph
power
the amount of work done in one second, or energy used in one second
power equation
P = w/t
unit for power
watts
unit for work
joules
what does the mechanical advantage of a simple machine tell you?
how much the input force is multipled to give you the output force