不明白p=fv

黑龍先帝

不明白p=fv
v係uniform 姐係net force=0 咁咪計唔到囉??

雞仔-bg

P=FV?
p係pressure?
f friction? frequency?
v velocity?

終極堂打雜

原帖由 雞仔-bg 於 2009-3-12 11:16 PM 發表
P=FV?
p係pressure?
f friction? frequency?
v velocity?

應該係Force x velocity

月愁云

有d唔明你想問物
如果用正常physics symboll
p=momentum
F=exerting foce 唔係net force!!!
v=velocity
P=power

p=mv
P=Fv
在此我估計你應該大細楷有問題
在P=Fv中
v是指average velocity
即係1/2(u+v)

舉一例:
a trolley is moving as a constant velocity 5ms-1 for 4s,the friction act on the trolley is 5N.find out the power devloped at the 4s.
因為constant velocity
NET FORCE=0
THUS,IT IS ACTING ON BY A CONSTANT FOCE 5N
P=Fv
=(5)(5)
=25W