Answer:
6.34×10⁹ seconds
Explanation:
Applying,
V = d/t............. Equation 1
Where V = speed plate, d = distance covered by the plate, t = time it takes the plate to travel
make t the subject of the equation
t = d/V............ Equation 2
From the question,
Given: d = 5 cm/yr = (5×3.154×10⁻⁹) = 1.577×10⁻⁸ m/s, d = 100 meter
Substitute these values into equation 2
t = 100/1.577×10⁻⁸
t = 6.34×10⁹ seconds
Hence the time it takes the the plate to travel is 6.34×10⁹ seconds
Answer:
The sound travels differently in different medium according the density of the medium.
Explanation:
The sound travels faster in dense medium and can be heard by the vibration of the bone present in the ear. The ear plugs reduce the sound intensity in both medium water and on land (air).
In air the sound is not heard properly due to the earplugs that stops the as the vibration are not able to produce as sound is not able to reach to middle ear, but Navy researchers have discovered that sound under water is heard by the bone present behind the ear, vibrations mastoid.
I think there caused by the gravitational pull on the earth from the moon
Answer:
b. a large elliptical galaxy
Explanation:
In elliptical galaxies the stars are grouped in an elliptical shape, it has a low quantity of gas and dust in comparison to spiral galaxies, and its stars belong to an old population, there is not new stellar formation in it.
The stars orbit in a messy way which made to believe that they form from the merger of galaxies.
They are also really massive (around 
solar masses).
The most massive and luminous can be found in the center of cluster of galaxies.
