A train is uniformly retarded from 35 m/s to 21 m/s over a distance of 350m. Calculate
A) The retardation
b) The total time taken under this retardation to come to rest from a speed of 35m/s
(Letts A level mathematics)
i got first part
v = 21
u = 35
s = 350
a = ?
21² = 35² + 700a
a = 441-1225/700
= -1.12 ms-2
The second part i cannot seem to get, i'm using the formula
s = ut + 0.5at²
350 = 35t + (0.5)(1.12)(t²)
350 = 35t + 0.56t²
0 = 0.56t²+35t-350
bang that in the quadratic formula and you get...
some wierd answers
can anyone help?