物理問題一問,好簡單

Take downward as positive
neglect air resistence.
acceleration = 10 ms-2

v^2 - u^2 = 2as

so v^2 = 2(1.5)(10)
v = 5.477 ms-1

so 著地前的速度係5.48ms-1

2008-06-11 16:27:18 補充：
By f t = mv - mu

Assume the dog doesn't rebound.

(2) f = 10 (5.477-0)

f = 27.4 N

v^2=u^2+2as
v^2=0+2(10)(1.5)
v^2=30
v=30的平方根




請問狗仔的終速為何?

它可以是0或正數。

若是0的話:
F=動量差/t
F=-(30的平方根)/2

0 . 7 5 m / s
3 0 k g