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3 years ago

How was the speed of light determined

2 answers:

5 0

Presently, the speed of light in a vacuum is defined to be exactly 299,792,458 m/s (approximately 186,282 miles per second). . An early experiment to measure the speed of light was conducted by Ole Romer, a Danish physicist, in 1676. Using a telescope, Ole observed the motions of Jupiter and one of its moons, Io

klemol [59]3 years ago

3 0

Answer:

Speed of light = 3 * 10 ^8 m / s. Speed is related to the distance and time and so its unit is in meters and seconds. The speed of light value mentioned above is the value calculated in vacuum or air with the help of lasers.

But when it comes to water, refractive index has to be taken into account.The speed of light is faster in vacuum than other mediums.

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A cannonball with a mass of 8.3 kg is fired from a cannon that has a mass of 949.3 kg. The cannonball is fired with a speed of 1

Fittoniya [83]

conservation of momentum
mass(ball) × speed(ball) = mass(cannon) × speed(cannon)
(8.3 kg) × (187.9 m/s) = (949.3 kg) × v
1.64 m/s = v

6 0

3 years ago

Which scientist is known for contributions to a scientific discipline that is different from that of the other three scientists?

Nookie1986 [14]

Archimedes is known for contributions to a scientific discipline that is different from that of the other scientists.

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3 years ago

In rural areas, water is often extracted from underground by pumps. Consider an underground water source whose free surface is 6

stealth61 [152]

Answer:

W = 9533.09 Watt

Explanation:

given,

diameter of pipe inlet, d₁ = 10 cm

r₁ = 5 cm

diameter of pipe outlet, d₂ = 15 cm

r₂= 7.5 cm

head upto water level is to rise = 60 + 5

= 65 m

flow rate = 0.015 m³/s

we know

A₁ v₁ = A₂ v₂ = Q

π r₁² v₁ = π r₂² v₂ = 0.015

$v_1= \dfrac{r_2^2}{r_1^2} v_2$

$v_1= \dfrac{7.5^2}{5^2} v_2$

$v_1= 2.25 v_2$

$v_2 = \dfrac{0.015}{\pi r_2^2}$

$v_2 = \dfrac{0.015}{\pi 0.075^2}$

v₂ = 0.848 m/s

v₁ = 1.908 m/s

Applying Bernoulli's equation

$P_p = \dfrac{1}{2}\rho (v_2^2-v_1^2)+ \rho g h$

$P_p= \dfrac{1}{2}\times 1000\times (0.848^2-1.908^2)+ 1000\times 9.8\times 65$

$P_p= 635539.32 Pa$

P_p is the pump pressure

Power of the pump

W = P_p x Q

W = 635539.32 x 0.015

W = 9533.09 Watt

6 0

4 years ago

How does the medium which a sound wave travels, affect a sound

arlik [135]

The density of a medium is the second factor that affects the speed of sound.

Please vote Brainliest (:

6 0

3 years ago

A ball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and pa

VLD [36.1K]

The ball takes 0.2 sec to travel the height of the window, which is 2 m.

Then the speed of the ball at that time was

$v = \frac{d}{t}$

$v = \frac{2}{0.20}$

$v = 10\ \frac{m}{s}$

We know that:

$v = v_0 -gt$

Where $v_0$ is the initial velocity.

So:

$10 = v_0 -9.8(2)$

$10 + 9.8(2) = v_0$

$v_0 = 29.6\ m / s$

Then we have the equation for the position as a function of time.

$r = r_0 + v_0t - \frac{1}{2}gt^2$

Where

$r_0$ = initial position

r = position as a function of time

$v_0$ = initial velocity

g = acceleration of gravity

t = time.

If the ball is thrown from the ground then:

$r_0$ = 0 m

We want to find now the distance between the window and the ground.

When the ball reaches the bottom of the window t = 1.8s

So:

$r = 0 + 29.6(1.8) - 0.5(9.8)(1.8)^2$

$r = 37,404$ m

The window is 37,404 m high

Finally, to know how high the ball rises we must know at what moment the vertical velocity of the ball is zero.

$v = v_0 -gt\\\\0 = v_0 -gt\\\\gt = v_0\\\\t = \frac{29.6}{9.8}$

$t = 3.02\ s$

Now we replace t in the position equation

$r = 0 + 29.6(3.02) -0.5(9.8)(3.02)^2$

$r = 44.70\ m$

The ball reaches up to 44.70 m in height.

3 0

4 years ago