energy. a. energy definition the ability to do work
TRANSCRIPT
B. Two Types of Energy
a. Kinetic Energy- the energy an object has due to its motion.
b. Potential Energy- energy that is stored in an object due to its position.
Example: a rolling ball.
Example: a bow and arrow.
Example: a battery.
C. Calculating Energy
a. Kinetic Energy =
Mass X Velocity2
2
K.E. = mv2
2
b. Units –mass= kilograms (kg)velocity = meters per second (m/s)
K.E. = Joules
c. Practice Problemsi. An 80 kg man is jogging at a velocity of
4 m/s. What is his kinetic energy?
K.E. = mv2
2
K.E. = 80 kg X (4 m/s)2
2K.E. = 80 kg X 16 m/s 2
K.E. = 640 J
ii. A 40 kg boy is jogging at a velocity of
4 m/s. What is his kinetic energy?
K.E. = mv2
2
K.E. = 40 kg X (4 m/s)2
2K.E. = 40 kg X 16 m/s 2
K.E. = 320 J
iii. A 40 kg boy is jogging at a velocity of 2 m/s. What is his kinetic
energy?
K.E. = mv2
2
K.E. = 40 kg X (2 m/s)2
2K.E. = 40 kg X 4 m/s 2
K.E. = 80 J
f. Practice Problems
i. A 22 Newton book is placed on a shelf that is 0.86 meters high.
P.E. = w x h
P.E. = 22 N x 0.86 m
P.E. = 18.92 J
ii. A 22 Newton book is placed on a shelf that is 1.86 meters high.
P.E. = w x h
P.E. = 22 N x 1.86 m
P.E. = 40.92 J