Question

A person accidentally leaves a car with the lights on. If eachof the two headlights uses 43 W andeach of the two taillights 7.0 W,for a total of 1.0E2 W, how longwill a fresh 12-V battery last if it is rated at 8.0E1 A·h? Assume the full 12 V appears across each bulb.

Other
ANSWERED
asked 2021-05-05
A person accidentally leaves a car with the lights on. If eachof the two headlights uses 43 W andeach of the two taillights 7.0 W,for a total of 1.0E2 W, how longwill a fresh 12-V battery last if it is rated at 8.0E1 A·h?
Assume the full 12 V appears across each bulb.

Answers (1)

2021-05-07
P = 100W
1 A*h = 3600 A*s (Coulombs), therefore:
Q = 288000 C
E = 12 V
For a battery, P=EI.
\(\displaystyle{I}=\triangle\frac{{Q}}{\triangle}{t}\)
Transposing these equations and solving for \(\displaystyle\triangle{t}\) the followingequation resolves:
\(\displaystyle\triangle{t}=\frac{{{E}\triangle{Q}}}{{P}}={34560}{s}={9.6}\) hours (So that's why theyhad it in A*h originally)
0
 
Best answer

expert advice

Have a similar question?
We can deal with it in 3 hours

Relevant Questions

asked 2021-04-02
A dead battery is charged by connecting it to the live battery ofanother car with jumper cables. Assume that V=9.5 V and R=0.90 Ohms.
Determine the current in the starter.
Your answer differs from the correct answerby orders of magnitude. A
Determine the current in the dead battery.
Your answer differs from the correct answerby orders of magnitude.
asked 2021-04-25
A wagon with two boxes of Gold, having total mass 300 kg, is cutloose from the hoses by an outlaw when the wagon is at rest 50m upa 6.0 degree slope. The outlaw plans to have the wagon roll downthe slope and across the level ground, and then fall into thecanyon where his confederates wait. But in a tree 40m from thecanyon edge wait the Lone Ranger (mass 75.0kg) and Tonto (mass60.0kg). They drop vertically into the wagon as it passes beneaththem. a) if they require 5.0 s to grab the gold and jump out, willthey make it before the wagon goes over the edge? b) When the twoheroes drop into the wagon, is the kinetic energy of the system ofthe heroes plus the wagon conserved? If not, does it increase ordecrease and by how much?
asked 2021-05-09
The dominant form of drag experienced by vehicles (bikes, cars,planes, etc.) at operating speeds is called form drag. Itincreases quadratically with velocity (essentially because theamount of air you run into increase with v and so does the amount of force you must exert on each small volume of air). Thus
\(\displaystyle{F}_{{{d}{r}{u}{g}}}={C}_{{d}}{A}{v}^{{2}}\)
where A is the cross-sectional area of the vehicle and \(\displaystyle{C}_{{d}}\) is called the coefficient of drag.
Part A:
Consider a vehicle moving with constant velocity \(\displaystyle\vec{{{v}}}\). Find the power dissipated by form drag.
Express your answer in terms of \(\displaystyle{C}_{{d}},{A},\) and speed v.
Part B:
A certain car has an engine that provides a maximum power \(\displaystyle{P}_{{0}}\). Suppose that the maximum speed of thee car, \(\displaystyle{v}_{{0}}\), is limited by a drag force proportional to the square of the speed (as in the previous part). The car engine is now modified, so that the new power \(\displaystyle{P}_{{1}}\) is 10 percent greater than the original power (\(\displaystyle{P}_{{1}}={110}\%{P}_{{0}}\)).
Assume the following:
The top speed is limited by air drag.
The magnitude of the force of air drag at these speeds is proportional to the square of the speed.
By what percentage, \(\displaystyle{\frac{{{v}_{{1}}-{v}_{{0}}}}{{{v}_{{0}}}}}\), is the top speed of the car increased?
Express the percent increase in top speed numerically to two significant figures.
asked 2021-01-15
A typical small flashlight contains two batteries, each having emf of 1.50 V connected in series with a bulb having a resistance of 14.0.
Part A
If the internal resistance of the battery is negligible, what power is delivered to the bulb?
Part B
If the batteries last for a time of 5.70 h, what is the total energy delivered to the bulb?
Part C
The resistance of real batteries increases as they run down.If the initial internal resistance is negligible,what is the combined internal resistance of both batteries when the power to the bulb has decreased to half its initial value? (Assume that the resistance of the bulb is constant. Actually, it will change some what when the current through the filament changes,because this changes the temperature of the filament and hence there sistivity of the filament wire.)
...