work/energy Flashcards
1
Q
define energy
A
the ability of a system to do work or to alter the surroundings in some way
2
Q
the law of conservation of energy
A
energy can’t be created/destroyed, only changed between forms
2
Q
define work
A
work is done when a force acts on an object and the object undergoes a displacement
2
Q
define negative force
A
when force acts opposite to motion of an object
e.g. kinetic friction always causes work in opposite motion
3
Q
cases of zero work
A
- no motion
- when force is perpendicular to displacement
- rocks in outer space (motion w/o force)
4
Q
define kinetic energy
A
- Ek
- energy an object has due to its linear motion
5
Q
work-energy theorem
A
work done on an object is equal to the object’s change in kinetic energy
6
Q
relationships of work-energy theorem
A
- if work greater than 0, object is accelerating
- if work less than 0, object is decelerating
- if work is 0, object is at constant speed
