Answer:
(a) 96 ft/s
(b) - 3072 ft/s^2
(c) 0.03125 s
Explanation:
h = 144 ft
u = 0 ft/s
g = 32 ft/s^2
(a) let she strikes the box with velocity v.
Use third equation of motion
[tex]v^{2}=u^{2}+2gh[/tex]
[tex]v^{2}=0^{2}+2\times 32 \times 144[/tex]
v = 96 ft/s
(b) Let the average acceleration is a.
initial velocity, u = 96 ft/s
final velocity, v = 0
h = 18 in = 1.5 ft
Use third equation of motion
[tex]v^{2}=u^{2}+2ah[/tex]
[tex]0^{2}=96^{2}+2\times a \times 1.5[/tex]
a = - 3072 ft/s^2
(c) Let the time taken is t.
Use first equation of motion
v = u + at
0 = 96 - 3072 x t
t = 0.03125 second
