While playing snowbarding a guy is going down a hill with 120 kmh. He then ends at the flat part of the hill, and his speed decreases with 6.5m/s^2 . Calculate the minumum lenght of the flat part.
+33616 Use v2 = u2 + 2*a*s where v = final speed (0 m/s), u = initial speed (120*103/3600 m/s) a = acceleration ( -6.5 m/s2) and s = distance (in metres).
Rearrange as: s = (v2 - u2)/(2a)
$${\mathtt{s}} = {\frac{\left({\mathtt{0}}{\mathtt{\,-\,}}{\left({\frac{{\mathtt{120\,000}}}{{\mathtt{3\,600}}}}\right)}^{{\mathtt{2}}}\right)}{{\mathtt{\,-\,}}\left({\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{6.5}}\right)}} \Rightarrow {\mathtt{s}} = {\mathtt{85.470\: \!085\: \!470\: \!085\: \!470\: \!1}}$$
or s ≈ 85.5 m
.
+33616 Use v2 = u2 + 2*a*s where v = final speed (0 m/s), u = initial speed (120*103/3600 m/s) a = acceleration ( -6.5 m/s2) and s = distance (in metres).
Rearrange as: s = (v2 - u2)/(2a)
$${\mathtt{s}} = {\frac{\left({\mathtt{0}}{\mathtt{\,-\,}}{\left({\frac{{\mathtt{120\,000}}}{{\mathtt{3\,600}}}}\right)}^{{\mathtt{2}}}\right)}{{\mathtt{\,-\,}}\left({\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{6.5}}\right)}} \Rightarrow {\mathtt{s}} = {\mathtt{85.470\: \!085\: \!470\: \!085\: \!470\: \!1}}$$
or s ≈ 85.5 m
.
