【简答题】试述特异性投射系统和非特异性投射系统的区别。
【单选题】Man's capacity for justice makes democracy possible, but man's ______to injustice makes democracy, necessary.
【单选题】A firm's capacity is the output:
A.
maximum that can be produced in the long-run.
B.
level where short-run average costs are minimized.
C.
level where long-run average costs are minimized.
D.
maximum that can be produced in the short-run.
【单选题】一辆以20m/s的速度在水平路面行驶的汽车,刹车过程中以大小为5m/s²的加速度作匀变速直线运动,则汽车在制动以后2S内与制动后6S内的位移之比是()
【简答题】一辆作匀加速直线运动的汽车,在6 s内通过相隔60 m远的两点,已知汽车经过第二点时的速率为15 m/s,则汽车通过第一点时的速率 v 1 =______________.
【简答题】一辆作匀加速直线运动的汽车,在 6 s 内通过相隔 60 m 远的两点,已知汽车经过第二点时的速率为 15 m/s,则 (1) 汽车通过第一点时的速率 =_______ _ _________ ; (2) 汽车的加速度a = .