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Mathematics
Problem
The height
h
h
h
(in metres) of a ball thrown upwards after
t
t
t
seconds is given by
h
(
t
)
=
−
4
t
2
+
8
t
h(t)=-4t^{2}+8t
h
(
t
)
=
−
4
t
2
+
8
t
. At what time(s) does the ball reach the ground? a)
t
=
0
s and
t
=
4
s
t=0\,\text{s} \text{ and } t=4\,\text{s}
t
=
0
s
and
t
=
4
s
b)
t
=
0
s and
t
=
2
s
t=0\,\text{s} \text{ and } t=\sqrt{2}\,\text{s}
t
=
0
s
and
t
=
2
s
c)
t
=
0
s and
t
=
2
s
t=0\,\text{s} \text{ and } t=2\,\text{s}
t
=
0
s
and
t
=
2
s
d)
t
=
1
s and
t
=
2
s
t=1\,\text{s} \text{ and } t=2\,\text{s}
t
=
1
s
and
t
=
2
s
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