被高空擲落的豆腐擊中會否致死？

[Let the building is 120 meter high , the weight of tofu a 0.5kg , gravitational acceleration is 9.8 ms-2]

V2 =U2 + 2aS
V2 =02 + 2(9.8)(120)
V2 = 2352 ms-1


by kinetic energy : K.E.=(1/2)mv2
K.E.=(1/2)(0.5)(2352)
K.E.=588N
Newton force unit=N (10N=1kg)

The tofu just like 58.8kg hurt on your head !


But not worried , because air have a resistance and the tofu structure is utterly soft , so it injury your head Minor only!!!!

Suppose the mass of the tofu is 0.5 kg and the height of the building is 120m,

By using v^2 = u^2 + 2aS

where u = 0
a = 9.8
S = 120

We get
v^2 = 2352
v = 48.5

That means the velocity of the tofu is around 48.5 ms-1 when hitting your head provided that there is NO air resistance.

Now, we have to find the force acting on your head,
it depends on the time elapsed between the tofu hits your head and it stops.

Assume, time elapsed = 2 sec

Force on your head = (mass of tofu) x (change in velocity) / (time elapsed)

= 0.5 x (48.5 - 0) / 2

= 12.125 N

That means around 12 N will act on your head, i.e. 1.2 kg OR 2.64 lb.

That's too small to hurt your head.

yan****** 兄

如果製造豆腐時落石膏粉太多，
或者豆腐被冰凍至聶氏溫度零下18度後(-18°C)，
或者豆腐被注入10成功力後(武俠小説)

然後
從 40 樓高空掉下擊中你個頭

我估一磚豆腐從 40 樓高空掉下,在未擊中你個頭之前,果件豆腐可能已被空氣嘅阻力壓碎.

這跟一句成語有關,,就如"以卵擊石"
如果在40樓高度對於一塊(剛體)而言(e.g 硬石塊),對人體必然造成巨大的傷害
這是考慮動量差與力之間的關係
先以作用力與反作用力對作解釋:人體受的力=豆腐受的力(方向相反)
此時豆腐與頭接觸的一刻,,發揮它軟的性質,會先變形...(延長撞擊時間)
再而裂開,粉碎...(又再延長撞擊時間)
跟據 力=動量差/時間
時間大大增長,令撞擊力大大減低
所以不會重傷和致命,,至於輕傷程式也太輕,,最多feel到細細力被拍左一下的感覺
畢竟你是頭,它是豆腐
記住如果樣野可以撞得碎既話,作用力必然大大減低