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3 years ago

The total amount of electrical energy used by a

Physics

2 answers:

tia_tia [17]3 years ago

7 0

The amount of electrical energy used by the television is given by:

$E=Pt$

where P is the power of the device and t is the time.

The power of the television is P=315 W, while the total time is

$t=30.0 min \cdot 60 =1800 s$

If we substitute these numbers into the formula, we find the energy:

$E=Pt=(315 W)(1800 s)=5.67 \cdot 10^5 J$

so, the correct answer is

(1) 5.67 × 10^5 J

Dmitriy789 [7]3 years ago

3 0

$W=Pt$
W - energy, P - power, t - time

$P=315 \ W \\
t= 30 \ min= 30 \times 60 \ s = 1800 \ s \\ \\
W=315 \times 1800=567000=5.67 \times 10^5 \ [J]$

The answer is (1).

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PLS HELP BEING TIMED!!!

Elodia [21]

Answer:

$K_{i}+U_{g,i} = K_{f}+U_{g,f}$

Explanation:

A closed system is a system where exists energy interactions with surroundings, but not mass interactions. If we neglect any energy interactions from boundary work, heat, electricity, magnetism and nuclear phenomena and assume that process occurs at steady state and all effects from non-conservative forces can be neglected, then the equation of energy conservation is reduce to this form:

$\Delta K +\Delta U_{g} = 0$ (1)

Where:

$\Delta K$ - Change in kinetic energy of the system, measured in joules.

$\Delta U_{g}$ - Change in gravitational potential energy of the system, measured in joules.

If we know that $\Delta K=K_{i}-K_{f}$ and $\Delta U_{g} = U_{g,i}-U_{g,f}$ , then we get the following equation:

$K_{i}+U_{g,i} = K_{f}+U_{g,f}$ (2)

Where $i$ and $f$ stands for initial and final states of each energy component.

Hence, the right answer is $K_{i}+U_{g,i} = K_{f}+U_{g,f}$

7 0

3 years ago

Read 2 more answers

A student throws a set of keys vertically upward to her sorority sister, who is in a window 3.50 m above. The second student cat

Mkey [24]

Answer:

a) 8.58 m/s upward

b) -2.211 m/s downward

Explanation:

Let gravitational acceleration g = -9.81m/s2. This is negative because it deceleration the upward motion of the key.

(a)We have the following equation of motion

$s = v_0t + gt^2/2$

where $v_0$ is the initial upward velocity of the keys, t = 1.1s is the time it takes for the keys to travel a distance of s = 3.5 m

$3.5 = v_01.1 - 9.81*1.1^2/2$

$3.5 = 1.1v_0 - 5.94$

$1.1v_0 = 3.5 + 5.94 = 9.44$

$v_0 = 9.44 / 1.1 = 8.58 m/s$

So the keys were thrown initially upward with a speed of 8.58 m/s

(b) If the initial velocity of the key is 8.58 m/s and it is subjected to a deceleration of 9.81m/s2 for 1.1s then the velocity right at the 1.1s instant is

$v = v_0 + gt = 8.58 - 9.81*1.1 = -2.211 m/s$

So they keys would have a downward speed of 2.211 m/s

5 0

3 years ago

Mike and Mitchell decide to have a foot race. They mark off a stretch of 100 yards, and recruit Cindy to work the stopwatch.

kati45 [8]

D)The boys had times that matched exactly

3 0

3 years ago

Read 2 more answers

How will a current change if the voltage in a circuit is held constant while the resistance doubles? 1. it's impossible to predi

laila [671]

According to Ohm's Law:

$I = \frac{V}{R}$

Where: V = Voltage
I = Current
R = Resistance

As you can see here, you can say that Current is directly proportional to Voltage and indirectly proportional to Resistance. This means that as the voltage increases, current increases and as the resistance increases, current decreases.

So in your scenario, if the voltage remains the same, but the resistance is doubled, that means that the current will be halved. So the answer to your question is 2. the current will drop to half of its original value.

4 0

3 years ago

If a sound wave is produced by a speaker at room temperature and has a

Oksana_A [137]

Answer: 183.8Hz

Explanation:

Given that,

wavelength of sound (λ) = 1.85 m

frequency of the sound (F) = ?

Recall that the speed of sound (V) in air is a constant with a value of 340m/s

So, apply the formula

V = F λ

340 m/s = F x 1.85 m

F = 340m/s / 1.85m

F = 183.8Hz

Thus, the frequency of the sound that is

generated is 183.8 hertz

3 0

3 years ago