Physics: how to do, thanks?

time to fall 1.2 m = √(2h/g) = √(2•1.2/9.8) = 0.495 s
distance to P = 2 m/s x 0.495 s = 0.990 m
vertical speed on hitting the ground v = √(2gh) = √(2•9.8•1.2) = 4.85 m/s
vertical speed after hitting = 0.9•4.85 = 4.36 m/s
time to reach second peak = t = v/g = 4.36/9.8 = 0.445 s
time to fall from second peak is same = 0.445 s
time in air after bounce = 2•0.445 = 0.891 s
distance PQ = 2 m/s x 0.891 s = 1.78 m


falling object starting from rest or reverse
h is height in meters, t is time falling in seconds,
g is acceleration of gravity, usually 9.8 m/s²
v is velocity in m/s
h = ½gt²
t = √(2h/g)
v = √(2gh)
h = v²/2g
v = gt