Answer:
97.03%
Explanation:
The equation for volumetric expansion due to thermal expansion is as follows
V/Vo=(1+γΔT)
V=final volume
Vo=initial volume
γ=coefficient of volume expansion=3.2 × 10–5 K–1
ΔT=
temperature difference
assuming that the earth is a sphere the volume is given by
V=(4/3)pi R^3
if we find the relationship between the initial and final volume we have the following
taking into account the previous equation
r/ro=(1+γΔT)^(1/3)
r/r0=(1-3.2x10-5(3000-300))^(1/3)=
r/ro=0.9703=97.03%
Answer:
Từ ánh sáng từ mặt trời đến nhiệt liên tục phát ra từ cơ thể chúng ta, có nhiều dạng bức xạ khác nhau. Tuy nhiên, khi nói đến bức xạ và nguy cơ ung thư, hầu hết mọi người đều nghĩ đến tia X và tia gamma.
Các nguồn tự nhiên của tia X và tia gamma bao gồm khí radon, chất phóng xạ trong lòng đất và các tia vũ trụ tấn công hành tinh từ không gian. Tuy nhiên, loại bức xạ này cũng có thể do con người gây ra. Tia X và tia gamma được sản xuất trong các nhà máy điện hạt nhân để sử dụng trong các xét nghiệm hình ảnh y tế, điều trị ung thư, chiếu xạ thực phẩm và máy quét an ninh sân bay với liều lượng nhỏ.
English:
From light from the sun to the heat that is continuously emitted from our bodies, there are many different forms of radiation. However, when it comes to radiation and cancer risk, most people think of X-rays and gamma rays.
Natural sources of X-rays and gamma rays include radon gas, underground radioactive material, and cosmic rays that strike the planet from space. However, this type of radiation can also be caused by humans. X-rays and gamma rays are produced in nuclear power plants for use in medical imaging tests, cancer treatments, food irradiation and airport security scanners in small doses.
Answer:
Approximately 
, assuming that the rocket had no propulsion onboard, and that air resistance on the rocket is negligible.
Explanation:
Initial velocity of this rocket: 
.
When the rocket is at its maximum height, the velocity of the rocket would be equal to 
. That is: 
.
The acceleration of the rocket (because of gravity) is constantly downwards, with a value of 
.
Let 
denote the distance that the rocket travelled from the launch site to the place where it attained maximum height. The following equation would relate 
to 
, 
, and 
:
.
Apply this equation to find the value of :
.
In other words, the maximum height that this rocket attained would be 
.
Again, assume that the air resistance on this rocket is negligible. The rocket would return to the ground along the same path, and would cover a total distance of 
.
Answer:
Add Ff from Fa
Explanation:
Fnet = sum of all force
horizontal net force = Ff + Fa
Answer:
True
Explanation:
In 2019 was taken the first image of a supermassive black hole in the center of the galaxy M87 with the Event Horizon Telescope, which is a network of radio telescope located in different points of the Earth, with the purpose of making a telescope of the size of the Earth.
A radio telescope is an antenna that is capable to perceive the light in the radio part of the electromagnetic spectrum¹.
It is important to notice that in the picture what it can be seen is the effect that the black hole has in the nearby stars.
Key terms:
¹Electromagnetic spectrum: decomposition of light in its different wavelengths (from radio waves to gamma rays).
