easy question

a) moving forwards with uniform backward acceleration , moving backwards with uniform forward acceleration , moving backwards with uniform backward acceleration , 這三個詞語分別點解????
moving forwards with uniform backward acceleration ＝
moving forwards with uniform deceleration
moving backwards with uniform forward acceleration =
moving backwards with uniform deceleration
moving backwards with uniform backward acceleration =
moving backwards with uniform acceleration

b) 在自由落體運動中 , 點解最高點的高度是零 ????
最高點是基準點，所以設定為零
希望解答到你 ^^