Compact fluorescent bulbs typically last 10 years while incandescent bulbs last about 1 year
For a given amount of light, a tungsten bulb draws 100 W and a compact
fluorescent bulb draws 15 W. If the cost of electricity is $0.10/kWh, how long would you
have to operate a compact fluorescent bulb to save $5.00 compared to the costs of operating
a tungsten bulb?
Let's look at this in terms of yearly operating cost. At $0.10/kWh the tungsten
bulb will draw energy in the amount 100 W x T x $0.10/kWh = $0.01/h x T. The compact
fluorescent will draw energy in the amount 15 W x T x $0.10/kWh = $0.0015/h x T. We
would look for $5.00 + $0.0015/h x T = $0.01/h x T. This is solved by gathering terms:
$0.01/h x T - $0.0015/h x T = $0.0085/h x T = $5.00
or
T = $5.00/$0.0085/h = 588.2 h.
If we factor in the bulb costs, we'd modify this to
$5.00 + $1.00 + $0.0015/h x T = $0.50 + $0.01/h x T.
In this case,
T = $5.50/$0.0085/h = 647.1 h.
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Exhibit 16-1
A graph of position versus time for an object oscillating at the free end of a horizontal spring is shown below.
?
?
Use this exhibit to answer the following question(s).
Refer to . The point at which the object has negative velocity and zero acceleration is
a.
A
b.
B
c.
C
d.
D
e.
E