a)
b)
#"given :"#
#v_i:"initial velocity of rock ; "v_i=15" "m/s#
#h:?#
#t:?#
c)
#"acceleration is g=-9.81 "m/s^2" (upward) and g=+9.81 "m/s^2 " (downward)" #
d)
#h=v_i*t-1/2*g*t^2#
#"plug t=1 "#
#h=15*1-1/2*9.81*1^2#
#h=15-4.905#
#h=10.095" meters"#
e)
#v=v_i-g*t#
#"plug "v=3 ,v_i=15#
#3=15-9.81*t#
#9.81 t=15-3#
#9.81t=12#
#t=12/(9.81)#
#t=1.22 "sec"#
f)
#-5=15-9.81*t#
#9.81t=15+5#
#9.81t=20#
#t=20/(9.81)#
#t=2.04 " sec"#