Мальчик бросил мяч вертикальное вверх с высоты 1,8 м с начальной скоростью 1,2м/сек. Высота (h), на которой находится мяч через t секунд полета , вычисляется по формуле H=-0,3gt^2+v0t+h0 где g примерно 10(м/с^2) v0-начальная скорость, h0-начальная высота
1)через сколько секунд мяч достигнет максимальной высоты?
2) на какую максимальную высоту поднимется мяч?
3) через сколько секунд камень упадет на землю?
4) на какой высоте будет стрела через 9 сек ?
at our lessons we answer the teacher's questions.
in england they don't go to school every day.
i do my homework in my bedroom.
the pupils on duty tidy the classroom.
all the pupils have to wear uniforms.
i come to school at a quarter to eight.
we like to make reports.
i do me homework every day.
i have my music lessons two times a week.
we have english three times a week.
this magazine is published to times a month.
i visit my aunt three times a month.
i never miss classes.
i go to the forest very often.
they seldom go to the theatre.
i don't want to answer the teacher's questions.
my friends and i go to school every day.
i do my homework at school.
every friday the students tidy their classrooms.
we don't have to wear a uniform at our school.
as a rule they come to school at 8 a.m.
my sister like to make reports on geography.
we must do washing up every day.
i have to play chess two times a week.
we go to a swimming pool three times a week.
my mother goes to the dentist two times a month.
i go to the disco three times a month.
i have never been to volgograd.
she goes to the cinema very often.
they seldom sing and dance.