Question #6f91b

2 Answers
Jul 1, 2015

I found the following values (in red in the explanation):
(but check carefully my math!!!)

Explanation:

Have a look:
enter image source here

Jul 2, 2015

Have a look if it is clearer.

Explanation:

Using the same diagram.
Considering that:
v_i=7.25 m/svi=7.25ms
h_1+h_2=25mh1+h2=25m
Use: v_f-v_i=atvfvi=at
0=7.25-9.81t_10=7.259.81t1
t_1=0.74st1=0.74s
Use:
h_1=v_it_1+1/2at_1^2h1=vit1+12at21
h_1=7.25*0.74-1/289.81(0.74)^2h1=7.250.741289.81(0.74)2
h_1=2.68m=2.7mh1=2.68m=2.7m

h_2=25-2.7=22.3mh2=252.7=22.3m
h=h_2-h_1=19.6mh=h2h1=19.6m
to fall down:
-h_2=-1/2*9.81t_2^2h2=129.81t22
t_2=2.13st2=2.13s
into v_f-v_i=atvfvi=at:
with v_i=0vi=0
v_f=21m/svf=21ms
and
T_(comp.te)=t_1+t_2=2.87sTcomp.te=t1+t2=2.87s