0?v2 |
2a1 |
0?302 |
2×(?0.6) |
勻減速運(yùn)動(dòng)的時(shí)間t1=
0?v |
a1 |
0?30 |
?0.6 |
(2)列車勻加速運(yùn)動(dòng)的位移:x2=
v2 |
2a2 |
302 |
2×1 |
勻加速運(yùn)動(dòng)的時(shí)間t2=
v |
a2 |
30 |
1 |
(3)這段位移若以30m/s速度運(yùn)行所需的時(shí)間t=
x1+x2 |
v |
750+450 |
30 |
這段位移實(shí)際所用的時(shí)間:t′=t1+t2+t3=50+30+60s=140s,
耽誤的時(shí)間:△t=t′-t=100s.
答:(1)列車減速運(yùn)動(dòng)時(shí)間為50s;
(2)列車加速運(yùn)動(dòng)的時(shí)間為30s;
(3)該列車由于臨時(shí)停車,共耽誤的時(shí)間為100s.