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3 years ago

Which situation describes the highest rate of power?

Physics

1 answer:

Darya [45]3 years ago

8 0

Answer : The correct option is, (D) A machine does 400 joules of work in 5 seconds.

Explanation :

Power : It is defined a the rate of doing work per unit time.

Formula used :

$P=\frac{w}{t}$

where,

P = power

w = work done

t = time

Now we have to determine the rate of power for the following options.

(A) A machine does 200 joules of work in 10 seconds.

$P=\frac{200}{10}=20W$

(B) A machine does 400 joules of work in 10 seconds.

$P=\frac{400}{10}=40W$

(C) A machine does 200 joules of work in 5 seconds.

$P=\frac{200}{5}=40W$

(D) A machine does 400 joules of work in 5 seconds.

$P=\frac{400}{5}=80W$

From this we conclude that, a machine does 400 joules of work in 5 seconds has the highest rate of power.

Hence, the correct option is, (D)

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What is the momentum of a car with a mass of 1,300 kg traveling at a speed of 28 m/s?

Vlad1618 [11]

Answer:

<h3>The answer is 36,400 kgm/s</h3>

Explanation:

The momentum of an object can be found by using the formula

<h3>momentum = mass × velocity</h3>

From the question

mass = 1,300 kg

speed / velocity = 28 m/s

We have

momentum = 1,300 × 28

We have the final answer as

Hope this helps you

7 0

3 years ago

1) Archeologists have found fossil remains of some of the first land

dimaraw [331]

Answer: Carbon 14 and Uranium 238 are not used together to determine fossil ages.

Explanation:

Carbon 14 with a half life of 5,700 years can only be used to date fossils of approximately 50,000 years. Most fossils are thought to be much older than 50,000 years. Also most fossils no longer contain any Carbon. The fossilized remains have been mineralized where the original organic material has been replaced and turned into stones containing no carbon.

Uranium 238 has a half life of 4.5 billion years. Uranium can be used to date the age of the earth. If 50% of pure uranium' is left in a sample the sample is assumed to be 4.5 billion years old.( This is assuming that the original sample was 100% uranium and no Uranium 238 has been eroded or lost in 4.5 billion years old. If a fossil has only 25 % of the Uranium 238 the sample has an estimated age of 3.2 Billion years. This would be the estimated age of the earliest life or formation of fossils.

Note no fossils contain Uranium 238. Uranium 238 is only found in igneous or volcanic rocks. So no fossils can be dated directly using U 238.

Because of the huge differences in the half lives of Carbon 14 and Uranium238 they cannot be used together. Carbon 14 can only be used to date fossils of a very recent age. Uranium 238 can only be used to date volcanic rocks of a very old age.

3 0

2 years ago

Calculate the critical angle for Zircon which has a refractive index of n = 2*

MA_775_DIABLO [31]

Answer:

Given that refractive index of the material is √2. i.e. n = √2. Hence, critical angle for the material is 45°

8 0

3 years ago

State ohm’s law Q.34.7

defon

Ohm's law states that: $V=RI$

Explanation:

Ohm's law states that in a conductor, the potential difference across the conductor is directly proportional to the current flowing through it. Mathematically,

$V \propto I$

where

V is the potential difference

I is the current

The constant of proportionality is called resistance (R), and it gives a measure of "how much the conductor opposes" to the flow of current. Therefore Ohm's law can be rewritten as

$V=RI$

where R is the resistance. By rewriting the equation as

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