Пружинный маятник вывели из положения равновесия и отпустили, через какое время кинетическоя энергия колеблющегося тела будет в первый раз ровна потенциальной энергии пружины. периуд колебаний равен 200 мс

Через 1/4 периода=50мс   еп=ек

ответ:

если надо ввыучить то выбери

объяснение:

can you imagine what our lives will be like in the year 2050? perhaps you will be flying off for a holiday on the moon, or maybe you will be taking your dog for a walk in the virtual reality.people will make friends through the internet. what is more, a large number of people will even come across their future husbands or wives in this way! computers will have become absolutely essential by 2050. even now, some people describe them as their best friend! others, however, say that we will become much more isolated from each other because we will have little real human contact.education will have changed a lot too. as more and more children will be using computers in schools, certain abilities, such as mental arithmetic will not be necessary since there will be computer programs. even writing by hand will have become a thing of the past.on the other hand, people seem to be quite optimistic about the benefits of genetic engineering, as they think scientists will use it to cure diseases like cancer and aids. if scientists manage to find a cure for these, we'll have a much healthier society. some people worry about the future, while others are full of hope and enthusiasm. no matter how dark or bright it may seem, it is up to us to look after our planet and try to make it a better place to live.

4) дано:  

ро ртути = 13600 кг/м^3

h = 76 м = 0.76 м

найти: p

решение:

p = ро * gh =  13600 кг/м^3 * 10 h/кг * 0.76 м = 103360 па

5) f = mg = 0.5 кг * 10 н/кг = 5 н

6) дано:

v = 30 л = 0.03 м^3

ро бензина = 700 кг/м^3

найти: m

решение:  

m = ро * v =  700 кг/м^3 *  0.03 м^3 = 21 кг

7) дано:  

m = 850 г = 0.85 кг

v = 140 см^3 =  0,00014 м^3

ро латуни = 8500 кг/м^3

найти: сплошной или полый

решение:

найдём плотность шара

ро = m/v =  0.85 кг/0,00014 м^3 = ~ 6071 кг/м^3 

6071 кг/м^3 < 8500 кг/м^3, значит полый

8)f = mg = 0.5 кг * 10 н/кг = 5 н