物理加速（acceleration）问题一辆汽车从静止状态开始,加速1.8m/s^2,加速时间为4.5秒.然后开始刹车,加速负1.9m/s^2,持续了两秒. 问这辆汽车一共行驶了多少米?
2019-06-19
物理加速（acceleration）问题
一辆汽车从静止状态开始,加速1.8m/s^2,加速时间为4.5秒.然后开始刹车,加速负1.9m/s^2,持续了两秒. 问这辆汽车一共行驶了多少米?
优质解答
X=v0t + 1/2 at^2
x1=0 + 1/2 x 1.8x 4.5^2=18.225m
v1(开始刹车时的速度）= v0 + at = 0 + 1.8x4.5=8.1m/s
x2=v1t + 1/2at^2=8.1x2 + 1/2x-1.9x2^2=12.4m
x=x1 + x2 =18.225 + 12.4 =30.625
X=v0t + 1/2 at^2
x1=0 + 1/2 x 1.8x 4.5^2=18.225m
v1(开始刹车时的速度）= v0 + at = 0 + 1.8x4.5=8.1m/s
x2=v1t + 1/2at^2=8.1x2 + 1/2x-1.9x2^2=12.4m
x=x1 + x2 =18.225 + 12.4 =30.625