All categories

3 years ago

The resistance of an electric heater is 50 Ω when connected to 120 V. How much energy does it use during 15 min of operation?

Physics

1 answer:

STALIN [3.7K]3 years ago

7 0

Answer:

Explanation:

I = V/R = 120 V/ 50 Ω = 2.4 A

P = VI = 120(2.4) = 288 W = 288 J/s

288 J/s (15 min(60s / min)) = 259,200 J

or the electric company would charge for

288 W / (1000 W/kW)•(15/60) hr = 0.072 kW•hr

At $0.20 / kW•hr, that would be under 1½ cents

You might be interested in

A car advertisement states that a certain car can accelerate from rest to

Evgen [1.6K]

Answer:

8 km/h²

Explanation:

a = v-u/t

v is final velocity, u is initial velocity

a = 40-0/5

a = 8.0 km/h²

5 0

3 years ago

7. A very wealthy donor decides to give a large sum of money to your college or university to build the world's largest visible-

FromTheMoon [43]

Answer:

the correct answer is d

on a tall, dry mountain peak

Explanation:

A telescope is an instrument that allows the observation of distant bodies whose light is very dim, for this the telescope concentrates a large amount of light with large diameter lenses or mirrors.

The location of a telescope must take into account several aspects:

* The most important that there are no nearby lights that disturb the observation, so it must be away from cities and other strong light sources.

* The climate should be as stable as possible with few temperature variations, to prevent the optical surfaces from fogging up and reducing the thermal expansion that changes the length of the instrument.

* You must choose a place with little rain and therefore little amount of clouds

Based on these needs we can answer which luxury will be the most suitable

a) There is a lot of light nearby

b) there is a lot of humidity and wind

c) there is a lot of light

d) This is an ideal place with low light, low humidity and stability in the climate

e) lots of humidity and light

so the correct answer is d

7 0

3 years ago

The chart shows data for four moving objects.

vesna_86 [32]

Answer:

Explanation:

by adding all the numbers

5 0

3 years ago

In the 4 X 100M relay, how long is the acceleration zone..

valkas [14]

Answer:it’s 400 meters

Explanation:

3 0

3 years ago

Two trains on separate tracks move toward each other. Train 1 has a speed of 145 km/h; train 2, a speed of 72.0 km/h. Train 2 bl

tekilochka [14]

Answer:

Therefore,

The frequency heard by the engineer on train 1

$f_{o}=603\ Hz$

Explanation:

Given:

Two trains on separate tracks move toward each other

For Train 1 Velocity of the observer,

$v_{o}=145\ km/h=145\times \dfrac{1000}{3600}=40.28\ m/s$

For Train 2 Velocity of the Source,

$v_{s}=90\ km/h=90\times \dfrac{1000}{3600}=25\ m/s$

Frequency of Source,

$f_{s}=500\ Hz$

To Find:

Frequency of Observer,

$f_{o}=?$ (frequency heard by the engineer on train 1)

Solution:

Here we can use the Doppler effect equation to calculate both the velocity of the source $v_{s}$ and observer $v_{o}$ , the original frequency of the sound waves $f_{s}$ and the observed frequency of the sound waves $f_{o}$ ,