设水平面长d斜面长为2H,则高为H,到斜面底端时速度为根号2gH,用时(根号2gH)/(0.5g)
划到停止时用时v/a=(根号2gH)/(0.1g),一共3秒,则有
(根号2gH)/(0.5g)+=(根号2gH)/(0.1g)=3,取g=10,可得
H=5/16,又有2gH-0=2*0.1g*d,得d=10H,于是S=d+2H=3.75m