Work, Power and Energy “I can” Statements
Work and Work Energy Theorem
1. I can calculate the work done by a specified constant force on an object that undergoes a
specified displacement. W= Fd
2. I can calculate the kinetic energy of one or more moving objects of specified mass and
speed.
KE= ½ mv2
3. I can calculate the change in kinetic energy (or speed) that results from performing a
specified amount of work on an object or vice versa. W= ΔKE W= ½ m (vf2 – vi2)
4. I can use the work-energy theorem to determine the force that is required to bring an
object to rest in a specified distance. W= ΔKE Fd= KEf - KEi OR Fd = ½ m (vf2 – vi2)
5. I can interpret a force vs. displacement graph and use it to calculate the work done.
W= area of a rectangle = length x width = Fd
OR W= area of a triangle= ½ Fd
Power
6. I can calculate the work performed by a force that supplies constant power.
P= W/t OR
E= Pt
7. I can calculate the average power supplied by a force that performs a specified amount of
work. P= W/t OR P= Fd/ t OR P = (mg)d/t
Springs
8. I can solve for the force exerted by a spring that obeys Hooke’s law. F= -kx
9. I can use a force vs. displacement graph to determine the spring constant of a spring that
obeys Hooke’s Law. slope of F vs. x graph is (k)
Potential Energy
10.I can solve for the potential energy of a stretched or compressed spring that obeys
Hooke’s Law.
PEe= ½ kx2
11.I can calculate the potential energy of one or more objects that are close to the surface of
the Earth.
PEg= mgh
Law of Conservation of Energy
12.I can identify situations in which the law of conservation of energy can be applied.
KEi + PEi = KEf + PEf
13.I can apply conservation of energy in analyzing the motion of objects that move under the
influence of springs. PEe= KE = PEg
14.I can apply conservation of energy in analyzing the motion of objects that move under the
influence of the gravitational force. KE = PEg
15.I can analyze situations in which an object’s mechanical energy is changed by friction.
KE ≠ PEg
PEg= KE + Heat (friction)
TEKS:
(6) Science concepts. The student knows that changes occur within a physical system and applies the
laws of conservation of energy and momentum. The student is expected to:
(A) investigate and calculate quantities using the work-energy theorem in various situations;
W= ΔKE
W= Fd
(B) investigate examples of kinetic and potential energy and their transformations;
KE= ½ mv2
PEg= mgh
ME= KE + PE
PEe= ½ kx2
(C) calculate the mechanical energy of, power generated within, impulse applied to, and
momentum of a physical system;
P= W/t
E= Pt
(D) demonstrate and apply the laws of conservation of energy
KEi + PEi = KEf + PEf