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:
Explanation:
Yesterday before i texted you it was like 11:00 and me and my friends were at the park and we were talking and there were like three boys and they came u to us and they said guess are size and i was like shoe size ? and they were like n ah you know what what i mean i just said i d k like how would i know and than my friend told them i was a v irgin and the may be like 30 min after they kept talking i just said im tired so i was going home and they invited them to there houses boys are like so weird in LA
Answer:
7 miles southwest
9 steps to the left
75 mph north
Explanation:
A vector quantity is any physical quantity that specifies the magnitude of the quantity and its direction.
So, the choices that gives a magnitude and direction are vectors.
The other type of physical quantities are the scalar which only specifies the magnitude but no direction;
9 steps to the left and 7 miles southwest are called displacement
75 mph north is velocity
This is the same question that I just answered.
Have present the definition of acceleration:
a = Δv / Δt, this is change in velocity per unit of time.
a and v are in bold to mean that they are vectors.
1) a body traveling in a straight line and increasing in speed: CORRECT:
Acceleration is the change in velocity, either magnitude or direction or both. So, a body increasing in speed is accelerated.
2) a body traveling in a straight line and decreasing in speed: CORRECT
A decrease in speed is a change in velocity, so it means acceleration.
3) a body traveling in a straight line at constant speed: FALSE.
That body is not changing either direction or speed so its motion is not accelerated but uniform.
4) a body standing still : FALSE.
That body is not changind either direction or speed.
5) a body traveling at a constant speed and changing direction: CORRECT.
The change in direction means that the body is accelerated. The acceleration due to change in direction is named centripetal acceleration.
