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3 years ago

What is the result of (6.2 × 10 4) x (3.3 × 10 2) expressed in scientific notation?

1 answer:

8 0

In scientific notation there are some rules;
1) the decimal point is comes to the first non-zero degit.
2) if the decimal point comes from left to right the power of ten must be negative.
3) if the decimal point comes from right to left then the power of 10 is possitive.
the numberyou wrote is an scientific form.you must say that expressed in standard form.write brother.

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The burner on an electric stove has a power output of 2.0 kW. A 650 g stainless steel tea kettle is filled with 20∘C water and p

True [87]

Answer:

The value is $V = 900 \ cm^3$

Explanation:

From the question we are told that

The power output is $P_{out} = 2.0 \ kW = 2.0 *10^{3} \ W$

The mass of the steel is $m= 650 \ g = \frac{650}{1000} = 0.650 \ kg$

The temperature of the water is $T = 20^o C$

The time take is $t = 2.70 \ minutes = 2.70 *60 = 162 \ s$

Generally the quantity of heat energy given out by the electric stove is mathematically represented as

$Q = P * t$

=> $Q = 2.0 *10^{3} * 162$

=> $Q = 324000 \ J$

This energy can also be mathematically represented as

$Q = \Delta T * m c_s * + m_w * c_w * \Delta T$

Here $c_s$ is the specific heat of stainless steel with value $c_s = 450\ J/C/kg$

tex]c_s[/tex] is the specific heat of water with value $c_s = 4180\ J/C/kg$

m_w is the mass of water which is mathematically represented as

$m_w = \rho_w * V$

=> $m_w = 1000 * V$

$324000 = (100 -20 ) * 0.650 * 450 * + 1000V * 4180 * (100-20)$

$V = 0.0008989 \ m^3$

converting to $cm^3$

$V = 900 \ cm^3$

8 0

3 years ago

It takes 3 minutes to make toast in a 1500 watt toaster. Calculate how much work is done by the toaster.

REY [17]

Answer: 2.7 x 10^5 joules

Explanation:

Given that:

Time taken = 3 minutes

convert time in minutes to seconds

(Since 1 minute = 60 seconds

3 minutes = 3 x 60 = 180 seconds)

Power of toaster = 1500 watt

Work done by the toaster = ?

Recall that power is the rate of work done per unit time

i.e Power = work/time

work = Power x Time

Work = 1500 watt x 180 seconds

Work = 270000J

Place the result in standard form

270000J = 2.7 x 10^5J

Thus, 2.7 x 10^5 joules of work is done by the toaster.

3 0

3 years ago

Ultrasound is used to scan the unborn baby of a pregnant mother.

hram777 [196]

Explanation:

Echo method formula for speed of sound : 2 x distance / time taken

2 x distance / 58 = 1540 m/s
2 x distance = 1540 m/s / 58 s
= 26.55172414 m
Distance = 26.55172414 / 2
= 13.27586207
= 13 m

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2 years ago

If you were on earth monitoring a person in a rocket ship traveling away from the earth at a speed close to the speed of light,

m_a_m_a [10]

Answer:

There wiil be a reduction in pulse and volume will be reduced

Explanation:

This is due to the relastivistic Doppler effect

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3 years ago

An asteroid, whose mass is 4.20×10⁻⁴ times the mass of Earth, revolves in a circular orbit around the Sun at a distance that is

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