Identify the reaction force

[Knight226]

Homework Statement

One or more external forces are exerted on each object enclosed in a dashed box shown in the figure below. Identify the reaction to each of these forces. (Assume that (a), (b) and (c) occur on Earth while (c), (d) and (e) occur far from any outside gravitational influences. Select all that apply.)

Homework Equations

Pairing reaction

The Attempt at a Solution

Diagram A shows a hand pulling a spring (see attachment)
The question is
(a) the spring exerts a force
upward on the Earth
to the right on the hand
to the left on the wall
to the right on the wall
to the left on the hand
downward on the Earth

The bold ones is my choice.
For diagram A, the hand is pulling the spring to the right, so, the spring exerts a force to the right of the hand, and to the right of the wall. I think I am very confused with the topic and the way how the words are phrased... when I think of the spring exerts a force to the right of the hand, I am taking the words in as the force exerted by the spring is working against the right of the hand...

The spring exerts a force to the right of the wall (the right is closer to the spring, so the spring has to push back an equal but opposite direction force right?)


Diagram B shows a woman pulling a wagon
The question is
(b) the wagon exerts a force
upward to the left on the handle
downward on the Earth due to gravitational attraction
upward on the Earth due to contact
downward to the left on the handle
upward on the Earth due to gravitational attraction
downward on the Earth due to contact


The bold ones is my choice.

This one I am really confused... I have made 3 selections, but the combination is incorrect.
The woman is pulling the wagon, so there should be an equal force pulling downward to the left on the handle.

Meanwhile, just like how bicycle moves forward because Earth propels it, the wagon exerts a force downward on the Earth due to contact.

I have added "downward on Earth due to gravitational attraction" because gravitational attraction is in play since the wagon is in contact right?...

Please help and correct me.
Thank you in advance.

 

[funnyguy]

a) Assuming the spring hasn't been compressed before, isn't the spring trying to return to its equilibrium position? If so, if you pull a spring right, why would its restoring force vector be in the same direction as the pulling force done by the hand? Try it out. Grab a spring, tie it to something and pull it with your hand. Compare the direction of its restoring force to the direction you are pulling. If you let go, what direction does its restoring force take it?

b) I'd assume there is some friction here, in which case, the "downward to the left on the handle " looks appropriate. You need to identify your forces. If you place an object on a surface here on Earth, what two forces act on it just sitting still on a surface. You probably know gravity is obvious, what is the second force? What direction do those two forces point?