Asked Dec 19, 2019

The cost of electricity varies widely throughout the United
States; $0.120/kWh is a typical value. At this unit price, calculate
the cost of (a) leaving a 40.0 - W porch light on for 2 weeks
while you are on vacation, (b) making a piece of dark toast in
3.00 min with a 970 - W toaster, and (c) drying a load of clothes
in 40.0 min in a 5 200 - W dryer.


Expert Answer

Step 1


Cost of electricity = $0.120 per kWh

Step 2

Calculating the cost of leaving a 40 W porch light on for 2 weeks:


Image Transcriptionclose

Energy consumed by the light in 2 weeks, 7days 24h lweek Iday E = Pt = (40W)x(2Weeksx- E = Pt = 13440Wh =13.44 kWwh E =13.44 kWh Cost of electricity = $0.120 per kWh $0.120 :=1.61$ Total required cost = (13.44 kWh)> 1kWh Total required cost =1.61$

Step 3

Calculating the cost of making a piece of dark toast in 3.00&n...


Image Transcriptionclose

Energy consumed in 3 minutes by a 970W toaster, 1h -) = 48.5Wh E = Pt = (970W)×(3minx- 60 min E= Pt = 48.5Wh = 0.0485 kWh E = 0.0485 kWh Cost of electricity = $0.120 per kWh $0.120 (0.0485 kWh)> = 0.00582$ Total required cost = 1kWh Total required cost =0.00582$


Want to see the full answer?

See Solution

Check out a sample Q&A here.

Want to see this answer and more?

Solutions are written by subject experts who are available 24/7. Questions are typically answered within 1 hour.*

See Solution
*Response times may vary by subject and question.
Tagged in



Related Physics Q&A

Find answers to questions asked by student like you
Show more Q&A

Q: In Rutherford's famous scattering experiments that led to the planetary model of the atom, alpha par...

A: When the alpha particle is at very far distance from the gold nucleus, potential energy will be negl...


Q: A toy gun uses a spring to project a 5.3 - g soft rubbersphere horizontally. The spring constant is ...

A: Let Wf  be the work done by the friction force in the opposite direction, Ps be the elastic potentia...


Q: A platinum resistance thermometer has resistances of 200.0 Ωwhen placed in a 0°C ice bath and 253.8 ...

A: Given data:Resistance at 0°C ice bath, R1 = 200.0 ΩLet resistance at room temperature be RoResistanc...


Q: A bicycle tire is spinning clockwise at 2.50 rad/s. During a timeperiod Δt = 1.25 s, the tire is sto...

A: a).The formula for the change in the tire’s angular velocity is,


Q: How does the speed affect the friction between a road and a skidding tire?

A: The friction force is the force that opposes the relative motion between the surfaces that are in co...


Q: In the dangerous “sport” of bungee jumping, a daringstudent jumps from a hot air balloon with a spec...

A: The potential energy of the student is


Q: A 0.280-kg volleyball approaches a player horizontally with aspeed of 15.0 m/s. The player strikes t...

A: (a) The impulse delivered to the ball by the player is


Q: When a rifle with longer barallel is fired, the force of expanding gases acts on the bullet for a lo...

A: The work done can be defined as the change in energy of the object or the product of force times the...


Q: A 40.0-kg child swings in a swing supported by two chains,each 3.00 m long. The tension in each chai...

A: Consider the figure of the swing system with all the provided values. The swing is at its lowest poi...