52.
v₀=54 km/h=15 m/s
v=v₀+at<=>0=15-t=>t=15 s
x=v₀t+at²/2=15*15-15²/2=112,5 m
53.
v₀=72 km/h=20 m/s
v=v₀+at<=>0=20+20a=>a=-1 m/s²
x=v₀t+at²/2=20*20-20²/2=200 m
