I live in a house. I really like my house. It's small, but I'm not small either. When you enter the house, you can see a small kitchen. In the kitchen, we cook and eat. I spend a lot of time in the kitchen Because I like to eat. the next room is the hallway. in the hallway there is a large closet on the entire wall. there are no Windows. we go through the hall to the other rooms. our hall is very large. there is a large sofa. the hall is very bright because there are many Windows. there are many different colors in the hall. my parents ' and sister's room is very large. They have one room. There is a large TV hanging there, it is located above the bed and there is a bedside table to the right of the bed. In the second half of the room is my sister's sofa. my room is the smallest. I even like it. my room has a pull-out sofa, a table, and a TV. there is a courtyard around the house. "My mother likes to grow flowers. we have a sauna in our yard. and we also have a dog that lives in a booth that dad built. We have a garage for my father's car and tools. We also store our things there.
Дано:
\(L=300\) м, \(S_1=2t+2,5t^2\), \(S_2=3t\), \(S_1(\tau)-?\)
Решение задачи:
Если тела движутся из двух разных точек A и B, причем навстречу друг другу, то сумма пройденных ими путей за время \(\tau\) до встречи равна расстоянию между этими точками \(L\), то есть:
S1(τ)+S2(τ)=L 2τ+2,5τ2+3τ=300 Решим это квадратное уравнение для нахождения времени до встречи: 2,5τ2+5τ–300=0 τ2+2τ–120=0 D=4+4⋅120=484 τ=–2±222 [τ=–12сτ=10с
Время не может быть отрицательным, поэтому откидываем первый корень. Для того, чтобы найти S1(τ) подставим найденное время в уравнение движения первого тела. S1(10)=2⋅10+2,5⋅102=270м ответ: 270 м.