Предмет: Физика, автор: AnaAnanas

При экстренной остановке поезда, который двигался со скоростью 36 км/ч, тормозной путь составил 12 м. Чему равен коэффициент трения между колесами поезда и рельсами? Помогите, очень нужно.

Ответы

Автор ответа: duadna23

S= Vot -at^2/2- торможение
а=( v-vo)/t
v=0- остановится,а v=10м/с
12=10t-(10/t)*t^2/2
12=10t-5t=5t
t=12/5=2,4 с. время торможения
а= -10/2=-4,2 м/с2
Fтр + F=0
м mg=-ma
м=-а/g=4,2/10=0,042

Автор ответа: MashaPutnaj

Дано Vo=36 км/ч=10 м/с S=12 м k- ?

S= (V^2-Vo^2)/2*a
a=-Fтр/m=-k*g
V=0
S=Vo^2/2*k*g
k=Vo^2*g*S=100/2*10*12=0,417
100% гарантии

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