FreedomJustice

引用:

原帖由 野孩子 於 2006-12-11 10:21 AM 發表
Of course is A

Corr Corr wor
but why ar

野孩子

引用:

原帖由 FreedomJustice 於 2006-12-11 06:50 PM 發表


Corr Corr wor
but why ar

When an object is changing direction
it has no velocity but it still have acceleration
due to the gravity
the acceleration is 10ms-2

Eraser

[Physic試題](heat)
Concept Test (2001)
A melting ice block of mass 0.05kg is mixed with x kg of water at 0(the temp) in a well -insulated container.
If 25000J of energy is supplied to the mixture , the mixture changes to water at 4(the temp)
Find the value
(Give: specific latent heat of fusion of ice = 3.34x10^5J/kg
S.H.C. of water = 4200J/kg)

Melting ice block = ice at 0 degree
the energy gain, 25000J = (the energy need for changing the 0.05kg ice into 0 degree water + the energy need for increasing 0.05+x kg water from 0 degree to 4 degree)
25000 = 0.05 * 3.34x10^5 + (0.05+x)*4200*4
x=0.44
ANS is B