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2 years ago

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Physics

1 answer:

NARA [144]2 years ago

4 0

Answer:

11,890

Explanation:

First we need to know what is considered a significant figure.

A significant figure is a value that is not a zero at the start OR end of a value.

Which means, the 0 in the value of 90 or 0.363 are not considered a significant figure.

The 0 in the value of 3056 is considered a significant figure.

So from the table, we can deduce:

0.275 has 3 significant figures

750 has 2 significant figures

$10.4 \times {10}^{5} = 1040000$

has 3 significant figures.

11,890 has 4 significant figures.

320,050 has 5 significant figures.

So from the above, we can already see the answer.

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Can spoon ring like a bell prove it

mote1985 [20]

Yes spoon can sound like a bell. To prove this, we perform an experiment.The handle of the spoon is tied at the mid point of the string, then wrap the ends of the string around pointer fingers. Now place fingers in ears. Lean over so that spoon hangs freely and swing the spoon so it taps against a door.
A sound is produced because the spoon vibrated, causing sound waves to travel up the string and into ears.

4 0

3 years ago

One speed skater starts across a frozen lake at an average speed of 8 m/s. Ten seconds later, a second speed skater starts from

Luba_88 [7]

Answer:

40 s

Explanation:

After 10 seconds, the first skater would have a 8m/s * 10s = 80 m head start

Let t be the number of seconds after the second skater starts will the second skater overtake the first skater

The distance traveled by the first skater after t seconds is

$s_1 = v_1t = 8t$

Similarly the distance traveled by the 2nd skater after t seconds is

$s_2 = v_2t = 10t$

Since the 2nd skater catches up to the 1st one after 80 m behind, the distance traveled by the 2nd one must be 80m greater than the distance of the 1st skater

$s_2 = s_1 + 80$

We can substitute $s_1 = 8t, s_2 = 10t$

$10t = 8t + 80$

$2t = 80$

$t = 80 / 2 = 40 s$

7 0

3 years ago

Light from the sun reaches the earth in 8.3 minutes. the speed of light is 3.0  108 m/s. in kilometers, how far is the earth fr

Flura [38]

To determine the distance of the light that has traveled given the time it takes to travel that distance, we need a relation that would relate time with distance. In any case, it would be the speed of the motion or specifically the speed of light that is travelling which is given as 3x10^8 meters per second. So, we simply multiply the time to the speed. Before doing so, we need to remember that the units should be homogeneous. We do as follows:

distance = 3x10^8 m/s ( 8.3 min ) ( 60 s / 1 min ) = 1.494x10^11 m

Since we are asked for the distance to be in kilometers, we convert

distance = 1.494x10^11 m ( 1 km / 1000 m) = 149400000 km

6 0

3 years ago

10. Almost three-quarters of household energy use is due to the following:

Arturiano [62]

Answer: Energy consumption and sustainability is important so that it remain available for future generation.

Explanation:

1. The home furnaces are likely to require fuel like coal, which will directly emit carbon dioxide and carbon monoxide gases. These should be replaced with the electrical furnaces. The old or more power consuming air conditioners should be replaced with new ones.

2. The water heaters should be tankless so their capacity to heat more water could be possible. The water heaters should be electricity saving.

3. Washer and dryers should be water savy and electricity savy. A front-loading washing machine is useful energy saver.

4. The LED lights are more electricity saving than conventional bulbs. Halogen lights are also electricity saving.

7 0

3 years ago

M84, M87, and NGC 4258 all have accretion disks around their central black holes for which the rotational velocities have been m

givi [52]

Answer:

For M84:

M = 590.7 * 10³⁶ kg

For M87:

M = 2307.46 * 10³⁶ kg

Explanation:

1 parsec, pc = 3.08 * 10¹⁶ m

The equation of the orbit speed can be used to calculate the doppler velocity:

$v = \sqrt{\frac{GM}{r} }$

making m the subject of the formula in the equation above to calculate the mass of the black hole:

$M = \frac{v^{2} r}{G}$ .............(1)

For M84:

r = 8 pc = 8 * 3.08 * 10¹⁶

r = 24.64 * 10¹⁶ m

v = 400 km/s = 4 * 10⁵ m/s

G = 6.674 * 10⁻¹¹ m³/kgs²

Substituting these values into equation (1)

$M = \frac{( 4*10^{5}) ^{2} *24.64* 10^{16} }{6.674 * 10^{-11} }$

M = 590.7 * 10³⁶ kg

For M87:

r = 20 pc = 20 * 3.08 * 10¹⁶

r = 61.6* 10¹⁶ m

v = 500 km/s = 5 * 10⁵ m/s

G = 6.674 * 10⁻¹¹ m³/kgs²

Substituting these values into equation (1)

$M = \frac{( 5*10^{5}) ^{2} *61.6* 10^{16} }{6.674 * 10^{-11} }$

M = 2307.46 * 10³⁶ kg

The mass of the black hole in the galaxies is measured using the doppler shift.

The assumption made is that the intrinsic velocity dispersion is needed to match the line widths that are observed.

3 0

3 years ago