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3 years ago

How many earth's are there in the universe??

Physics

1 answer:

loris [4]3 years ago

8 0

Just one the earth is the only one like it it's completely unique

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With what force will a car hit a tree if the car has a mass of 3,000 kg and it is accelerating at a rate of 2m/s2

Arisa [49]

<span>F=ma = 3000x2m/sec^2 =6000 newtons. </span>

6 0

3 years ago

The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme a

Tanzania [10]

Answer:

1) tensile stress = 76.648 Mpa

2) extension = 0.0215 m

Explanation:

Detailed explanation and calculation is shown in the image below

5 0

4 years ago

One of the harmonics on a string 1.30m long has a frequency of 15.60 Hz. The next higher harmonic has a frequency of 23.40 Hz. F

Alja [10]

Answer:

$\large \boxed{\text{(a) 7.800 Hz; (b) 20.3 m/s; 40.6 m/s; 60.8 m/s}}$

Explanation:

a) Fundamental frequency

A harmonic is an integral multiple of the fundamental frequency.

$\dfrac{\text{23.40 Hz}}{\text{15.60 Hz}} = \dfrac{1.500}{1} \approx \dfrac{3}{2}$

$f = \dfrac{\text{24.30 Hz}}{3} = \textbf{7.800 Hz}$

b) Wave speed

(i) Calculate the wavelength

In a fundamental vibration, the length of the string is half the wavelength.

$\begin{array}{rcl}L & = & \dfrac{\lambda}{2}\\\\\text{1.30 m} & = & \dfrac{\lambda}{2}\\\\\lambda & = & \text{2.60 m}\\\end{array}$

(b) Calculate the speed s

$\begin{array}{rcl}v_{1}& = & f_{1}\lambda\\& = & \text{7.800 s}^{-1} \times \text{2.60 m}\\& = & \textbf{20.3 m/s}\\\end{array}$

$\begin{array}{rcl}v_{2}& = & f_{2}\lambda\\& = & \text{15.60 s}^{-1} \times \text{2.60 m}\\& = & \textbf{40.6 m/s}\\\end{array}$

$\begin{array}{rcl}v_{3}& = & f_{3}\lambda\\& = & \text{23.40 s}^{-1} \times \text{2.60 m}\\& = & \textbf{60.8 m/s}\\\end{array}$

4 0

3 years ago

Which of the materials would be able to scratch Quartz

Lelechka [254]

<span>anything harder than mohs scale 7 so eg Topaz, Corundum and diamond representing mohs scale 8 9 and 10 respectively.</span>

7 0

3 years ago

if you put a pencil in a cup of water, it looks as if it is broken and larger in the water. This is because light waves

vladimir1956 [14]

Answer:

When light enters from air to water i.e. it is moving from rarer to denser medium, it changes its original path as there is a change of speed of light and deflects itself towards the normal. This is known as the refraction of light and this is why a pencil in a cup of water looks as if it is broken and larger.

Explanation:

5 0

3 years ago