Jawapan

2016-08-20T22:07:27+08:00
V=0
u=20ms^-1
a=-10ms^-2 (negatif sbb dilontar ke atas)
guna: v^2=u^2+2as
0=20^2+2(-10)s
0=400-20s
-400=-20s
s=20m