Work and Energy Flashcards
It is the ability to do work.
Energy
It is done by a constant force on an object is defined as the product of the component of the force along the direction of displacement and the magnitude of the displacement.
Work
It is associated with the position of the object.
It is the energy associated with the relative position of an object in space near the Earth’s surface.
Gravitational Potential Energy
It is energy of motion.
Kinetic Energy
The total mechanical energy of an object remains constant as the object moves, provided that the net work done by external nonconservative forces is zero.
Conservation of Mechanical Energy
If the work it does on an object moving between two points depends on the path of the motion between the points e. g. static and kinetic frictional forces, air resistance
Non-conservative force
It states that the work is done by the external force on an object is equal to the object’s change in kinetic energy.
Work-energy theorem
Kyle enjoys hiking on a mountain every weekend. One day, while standing on a cliff, he dropped a stone to estimate the cliff’s height.
What happens to the potential energy of the stone as it falls to the ground?
A. The potential energy increases.
B. The potential energy is lost.
C. The potential energy was changed to kinetic energy.
D. It was stored as potential energy.
C.
If you hold a heavy bag of groceries in your hand at rest, you do no work on it. How does it happen?
A. You do exert a force on the bag, but the displacement of the bag is zero, so the work done by you on the bag is zero.
B. You exert an upward force on the bag equal to its weight. But this upward force is perpendicular to the horizontal displacement of the bag and thus is doing no work.
C. You start walking, there is a horizontal acceleration and you do briefly exert a vertical force and does do not work on the bag.
D. All of the above.
