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3 years ago

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The total yearly world consumption of energy is approximately 4.0 Ã— 1020 J. How much mass would have to be completely converted

into energy to provide this amount of energy?

1 answer:

BabaBlast [244]3 years ago

6 0

Answer:

m = 4.4 × 10³ kg

Explanation:

Given that:

The total yearly energy is 4.0 × 10²⁰ J

The amount of mass that provides this energy can be determined by using the formula:

E = mc²

where;

c = speed of light in free space = (3 × 10⁸)

4.0 × 10²⁰ = m × (3 × 10⁸)²

$m = \dfrac{4.0 \times 10^{20} }{(3\times 10^8)^2}$

m = 4.4 × 10³ kg

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vampirchik [111]

My guess would be choice D

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3 years ago

A stone is dropped from a bridge abd it hits the water 2.2 seconds later how high is the bridge above the water

Bess [88]

Answer:

h = 23.716 m

Explanation:

Given that,

The time taken by the stone to hit the water is, t = 2.2 s

Height of the bridge above the ground, h = ?

The distance that the body will fall through the time is given by the formula

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Substituting the values in the above equation

S = 1/2 x 9.8 m/s² x (2.2 s)²

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Therefore, the height of the bridge from the surface of the water is h = 23.716 m

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3 years ago

As 390 g of hot milk cools in a mug it transfers 30 000 j of heat to the environment. whats is the temperature change of the mil

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You have to use the specific heat equation.

Q = cmΔT where Q is the energy, c is specific heat, m is mass, and ΔT is change in temp.

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Solving for ΔT, we get:

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3 years ago

You look down an old well, cannot see the bottom, and mutter to yourself "Oh well!". In order to estimate the depth of the well,

telo118 [61]

Answer:

The best estimate of the depth of the well is 2.3 sec.

Explanation:

Given that,

Record time,

$t_{1}=2.19\ sec$

$t_{2}=2.30\ sec$

$t_{3}=2.26\ sec$

$t_{4}=2.29\ sec$

$t_{5}=2.27\ sec$

We need to find the best estimate of the depth of the well

According to record time,

We can write of the record time

$t_{1}=2.19\approx 2.2\ sec$

$t_{2}=2.30\approx 2.3\ sec$

$t_{3}=2.26\approx 2.3\ sec$

$t_{4}=2.29\approx 2.3\ sec$

$t_{5}=2.27\approx 2.3\ sec$

Here, all time is nearest 2.3 sec.

So, we can say that the best estimate of the depth of the well is 2.3 sec.

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3 years ago

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Arada [10]

Answer : The final temperature is, $25.0^oC$

Explanation :

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3 years ago