Download 8.8.b Conservation of Energy 2

8.8.b Conservation of Energy 2
SWBAT apply the Law of Conservation
of Energy to different situations in an
effort to calculate unknown variables.
A 5 kg block is pushed up
against a spring and
released.
The spring has a constant
k = 30 N/m and was
compressed 0.1 m.
What is the velocity of the
block when the spring
reaches it’s equilibrium
position?
1.
3.
a.
b.
c.
d.
Diagram
121.5 J
121.5 J, 0 J
4.1 m
2.
a.
b.
c.
d.
980 J
686 J
294 J
17.1 m/s
a.
b.
c.
d.
0.35 J
0.35 J
0.35 J
1.8 m
4.
a.
b.
c.
d.
Diagram
5.4 J
5.4 J, 0 J
1.6 m/s
5. 35.1 J
6. 4.9 J
• A simple pendulum consists of a mass (called a bob)
hung by a string from a fixed support.
• It hangs vertically in its equilibrium position.
• When the bob is displaced from equilibrium and
then released, it begins a back and forth motion
about its fixed equilibrium position.
Classic Physics Demos:
https://www.youtube.com/watch?v=BVxEEn3w688
https://www.youtube.com/watch?v=mhIOylZMg6Q
Max PE
Max PE
Min PE
Min KE
Max PE
Min PE
Min KE
Max KE
Min KE
Max KE
Energy of a Pendulum
A ball is released from the top of a ramp.
How high does the ball go as it rolls up the other side?
Energy of a Roller Coaster
A pendulum is made from a
2.0-kilogram mass attached to
a rope. The mass is pushed to
the side until it is at position A,
3 meters higher than its
equilibrium position. What is
the total amount of kinetic
energy that the mass has as it
swings freely through its
equilibrium position? What is
the maximum velocity that the
bob reaches?
2 kg
3m