Energy Flashcards
(15 cards)
What is work?
When a force acts upon an object to cause a displacement of said object, work was done upon the object.
What is the equation that represents work?
work = force x displacement x cosine of theta
What is kinetic energy?
Energy that is in motion
What is the equation to calculate kinetic energy?
Ek = 1/2 mv^2
Ek is measured in…
Joules (J)
= kg m^2/s^2
What is positive work?
theta
What is negative work?
theta > 90 degrees
cosine theta is negative
What is zero work?
theta = 90 degrees
cosine theta is zero
What is the work energy theorem?
work = change in kinetic energy *W = delta Ek*
What is gravitational potential energy?
The energy stored in an object due to its position in a gravitational field
What is the equation that represents gravitational potential energy?
Gravitational potential energy = mass [kg] x gravitational field [N/kg] x change in height [m]
delta Eg = mg deltah
Why is gravitational potential energy always written as deltaEg?
Only the change in height is important. The reference point does not matter, therefore we can set h = 0m at any point (as long as point remains consistent throughout problem).
The value of Eg is not important, only deltaEg is significant.
What is energy conservation?
Energy cannot be created or destroyed
What is the total mechanical energy of an object?
E total = E kinetic + E grav
What happens when there are no non-conservative forces acting on an object?
E total is constant.
Therefore,
E total initial = E total final
