จำนวน 2 ความเห็น, หน้า่ | -1-

ความเห็นเพิ่มเติมที่ 1 28 ส.ค. 2550 (08:23)
Think about the physics of the problem. What allows the monkey to move at a certain acceleration? He does not touch anything but the rope, right? So, the rope is the force transmitter! Now, let T be the rope linear tension. The mass of monkey is m and that of the object hung at the other end of the rope is M. Suppose a is the acceleration of the monkey when he is climbing.

1) T - mg = total force acting on the monkey = ma.
The object starts to move, hence, T = Mg.
Therefore, Mg = m(g+a). Thus, a = (M/m - 1)g. It is your task to get the numerical value.

2) Once the monkey stops climbing, he must experience the drawing from the object. Denoting by a' is his present acceleration. Clearly, the mass M' is also moving at the same acceleration. Therefore,
T - mg = ma', and
T - Mg = -Ma'.
The negative sign in front of the latter equation represents the downward direction. Therefore, M(g-a') = T = m(g+a').
Solving the equation, one obtains
a' = (M-m)/(M+m)*g.
The rest is your work.

ความเห็นเพิ่มเติมที่ 2 29 ส.ค. 2550 (23:18)
THANK YOU

i can here