Calculating Acceleration for a Monkey Lifting a Crate | Force and Motion

[pinkxoxo]

1. THE PROBLEM: A 9 kg monkey climbs up a massless rope that runs over a frictionless tree limb and back down to a 21 kg package on the ground (Fig. 5-54).

Figure 5-54.

(a) What is the magnitude of the least acceleration the monkey must have in order to lift the package off the ground?
m/s2

Assume that after the package has been lifted, the monkey stops its climb and holds onto the rope.

(b) What is the monkey's acceleration?
m/s2
(c) What is the tension in the rope?
N


2.) MY ATTEMPTS: I figured that in order for the monkey to be able to lift the crate its acceleration should be proportional to where the monkey and crate had the same force.
F=ma=m(Monkey(9))(a)=m(Crate(21))(9.8)
a=22.876 m/s^2...according to web assign I am wrong! I can solve the other parts of the problem if I knew how to find the first acceleration
PLEASE HELP :)

 

[Redbelly98]

(a) To start, I would calculate what the rope tension must be in order to just start lifting the package.

 

[pinkxoxo]

How would i calculate that? F=ma but the only a i see given is gravity?

 

[Redbelly98]

Well, to put it another way: what would be the force required to lift anything off of the ground?

 

[HalfThere]

F = ma is key. And there IS another a apart from gravity. Hmmm, what could be accelerating in the problem?