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3 years ago

How was the gravitational constant G first determined

1 answer:

6 0

<span>In equation form, this is often expressed as follows: The constant of proportionality in this equation is G - the universal gravitation constant. The value of G was not experimentally determined until nearly a century later (1798) by Lord Henry Cavendish using a torsion balance.</span>

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An astronaut is traveling in a space vehicle that has a speed of 0.480c relative to Earth. The astronaut measures his pulse rate

Alexxandr [17]

Explanation:

The heart rate of the astronaut is 78.5 beats per minute, which means that the time between heart beats is 0.0127 min. This will be the time t measured by the moving observer. The time t' measured by the stationary Earth-based observer is given by

$t' = \dfrac{t}{\sqrt{1 - \left(\dfrac{v^2}{c^2}\right)}}$

a) If the astronaut is moving at 0.480c, the time t' is

$t' = \dfrac{0.0127\:\text{min}}{\sqrt{1 - \left(\dfrac{0.2304c^2}{c^2}\right)}}$

$\:\:\:\:=0.0145\:\text{min}$

This means that time between his heart beats as measured by Earth-based observer is 0.0145 min, which is equivalent to 69.1 beats per minute.

b) At v = 0.940c, the time t' is

$t' = \dfrac{0.0127\:\text{min}}{\sqrt{1 - \left(\dfrac{0.8836c^2}{c^2}\right)}}$

$\:\:\:\:=0.0372\:\text{min}$

So at this speed, the astronaut's heart rate is 1/(0.0372 min) or 26.9 beats per minute.

8 0

2 years ago

The critical angle for total internal reflection occurs when:___________.

Anastaziya [24]

Answer:

b) the refracted ray has an angle of 90 degrees

Explanation:

The angle of incidence is measured with respect to the normal separation of the media. The critical angle for total internal reflection occurs is:

$\theta=arcsin(\frac{n_2}{n_1})$

Here $n_2$ and $n_1$ are the refractive index of the mediums. This equation is an application of Snell's law, for the case where the refracted ray has an angle of $90^\circ$ .

5 0

2 years ago

A 100-m-long wire carrying a current of 4.0 A will be accompanied by a magnetic field of what strength at a distance of 0.050 m

solong [7]

Answer:

1.6 x 10^-5 T

Explanation:

i = 4 A

r = 0.05 m

The magnetic field due to long wire at a distance r is given by

$B = \frac{\mu _{0}}{4\pi }\times \frac{2i}{r}$

B = 10^-7 x 2 x 4 / 0.05

B = 1.6 x 10^-5 T

3 0

3 years ago

What is dark energy and what evidence do astronomers have that it is an important component of the universe?

PSYCHO15rus [73]

Answer:

The existance of dark energy was suggested to help explain measurements, using Type Ia supernovae as distance indicators, that the expansion of the universe is speeding up and its acceleration requires a source of energy. Scientists suggested that It may be a new form of energy for which there is not yet a theoretical explanation. quantum mechanics predict that it may be the vacuum energy associated with "empty" space itself.

8 0

3 years ago

Opal adds 25 grams of salt to a one-liter glass beaker filled up to its volume mark with pure water. She stirs the water until t

Mars2501 [29]

By what i know i think that the answer would be A a homogeneous mixture.

5 0

3 years ago