# Solving Forces Confusion: Finding Chris's Force on Chair

• AznBoi
In summary, the problem involves an inventive child named Chris who wants to reach an apple in a tree without climbing the tree. With a chair connected to a rope over a frictionless pulley, Chris pulls on the rope with a force of 250 N. His true weight is 320 N and the chair weighs 160 N. The question is how to find the force that Chris exerts on the chair. After calculating the acceleration of the forces to be .408m/s^2, it is determined that Chris exerts a force of approximately 83.3 N. However, it is unclear how Chris will actually reach the apple with this setup.
AznBoi
I'm confused on this problem, I have found the acceleration of the forces, but I'm stuck with the the question below. Thanks for your help!

Problem:
An inventive child named Chris wants to reach an apple in a tree without climbing the tree. Sitting in a chair connected to a rope that passes over a frictionless pulley, Chris pulls on the loose end of the rope with such a force that the spring scale reads 250 N. Chris's true weight is 320 N and the chair weights 160 N.

How do you find the force Chris exerts on the chair?

I found the accelerationg of the forces, .408m/s^2

First of all, I know that his weight(320N) is being pushed down onto the chair. The chair also pushes him back up with (20 N, .408m/s^2 acceleration) Do I need to count in gravity also??

The answer is 83.3 N approx and I know a combination of numbers that would allow me to get that answer:

340N / .408 m/s^2 x 10m/s^2

I guess that isn't right? because the result would be in mass?? Help please.

Where is the spring scale? What is it measuring?

It is measuring 250 N

AznBoi said:
It is measuring 250 N
Right. But is he supposed to pull himself and the chair up to the apple, or is he simply pulling on a rope that is measuring the magnitude of the force he applies?

I'm failing to see how he's going to get the apple, short of throwing the chair at it (which, oddly enough, would take less force than pulling the two of them up to it).

well the rope is attachd to the chair and he is sitting on the chair

and yes therefore he would be pulling the chair with himself up to the apple

## 1. What is the definition of force?

Force is a physical quantity that describes the interaction between two objects or bodies. It can cause a change in the motion or shape of an object.

## 2. How do you calculate the force on an object?

The force on an object can be calculated using the formula F=ma, where F is the force, m is the mass of the object, and a is the acceleration of the object.

## 3. Why is it important to know the direction of the force?

The direction of the force is important because it determines the motion of the object. If the force is in the same direction as the object's motion, it will accelerate the object. If the force is in the opposite direction, it will decelerate the object.

## 4. How do you find the force on an object in a system with multiple forces?

To find the force on an object in a system with multiple forces, you can use vector addition. This involves breaking down each force into its x and y components and then adding them together to find the net force on the object.

## 5. What are some common units of force?

Some common units of force include Newtons (N), pounds (lb), and dynes (dyn). Newtons are the standard unit of force in the International System of Units (SI).

Replies
6
Views
3K
Replies
2
Views
4K
Replies
5
Views
29K
Replies
39
Views
3K
Replies
19
Views
1K
Replies
25
Views
4K
Replies
4
Views
1K
Replies
6
Views
2K
Replies
38
Views
3K
Replies
1
Views
3K