[填空题]
A stone is thrown vezek3oe0 bpd p06q cb, tn23,jorticallha :s37uhdb.bx u;5ocly o)dx h:22ary upward with a speed of 18.0 m/s
(a) How fast is it moving when it reaches a height of 11.0 m? |v| = m/s
(b) How long is required to reach this height? t = s, s
(c) Why are there two answers to (b)?