Answer:
hai điện tích điểm bằng nhau có độ lớn 6.10^-8C đặt cách nhau một khoảng là r trong dầu hỏa có hằng số điện môi E=2,1. Lực tương tác tĩnh điện giữa chúng laf3,85.10^-4. tìm r
When smoke particles pass between the source of radiation and the detector the drop in radiation will be sufficient to tigger the alarm. <span />
A conductor is something which allows electricity to pass through it
an example is a coin
An insulator is something which cannot allow electricity to pass through it
an example is plastic (or plastic cotton reel, plastic container ect.)
Static electricity is when you rub two things together to create static
I'm not sure if i helped on the last question but i am definitely sure of the first ones
The hidden gene is called recessive
Answer:
The answer is 0.83 seconds.
Explanation:
The formula of free fall is following:

Where g=9.8 m/s^2 and t=2 seconds, the rock takes:

19.6 meters. This is the half distance of the cliff. The whole distance is 39.2 meters. So it takes:

2.83 second to fall down completely. The rock takes the second half of the cliff in 0.83 seconds