Work, Energy & Power Flashcards
If the angle between the applied force and displacement is 90 degrees, what is the amount of work done on the object?
0 J. No work is done on the object
What is the formula used to calculate work done on an object?
W = Fxcos@
How can you calculate the net work done by two or more forces?
Approach1: Calculate the work done by each force first, then add them up taking into account the signs
Approach2: Calculate the resultant force from all the forces, then calculate the work from the resultant force.
What does the work-energy theorem state?
It states that the work done on an object by the net force is equal to the change in its kinetic energy.
What is the definition of power and what is the equation used to define power?
Power is defined as the rate at which work is done.
P = W/t
What is a non-conservative force and what are some examples?
A non-conservative force is a force that changes an object’s mechanical energy. Examples are friction, applied force and air resistance.
What is the relationship between work done by non-conservative forces, change in kinetic energy and change in potential energy?
W(non-conservative) = change in potential energy + change in potential energy
When is negative work done?
When the applied force acts in the opposite direction of the displacement of the object. For example, an object subjected to frictional force.
What is the unit of power?
Watt
What is the other formula used to calculate power?
P = Fv
