Question

explicati pls,am nevoie pe maine

Answer 1

v²=v0²-2*a*s

In momentul opririi in gara, v=0 deci

v0²=2*a*s de unde

s=v0²/2*a

v0=72kn/h=20m/s (am luat 72km/h pentru a obtine un rezultat fara zecimale! Poti reface calculele cu datele prob

Answer 2

vo=72 km/h=20 m/s

Vectorial: G+N=ma

Scalar:Ox:-Ff=ma

Oy:N-mg=0=>N=mg

Ff=μN=μmg

-μmg=ma |:m=>a=-μg=-0,1•9,8=-0,98 m/s^2

v=vo+at<=>0=20-0,98t=>t=20/0,98=20,4 s

v^2=vo^2+2ad<=>0=400-1,96d=>d=400/1,96=204 m