Solving the Friction Wagon Homework Problem

In summary, to find the mass of the child in a wagon being accelerated at 1 [m/s2], you must first find the mass of the wagon by itself using Newton's second law. Then, using the mass of the wagon and the total mass of the wagon+child (found by solving for the mass of the wagon and the child together when the acceleration is 5 [m/s2]), you can solve for the mass of the child alone using Newton's second law again.
  • #1
homevolend
47
0

Homework Statement



A wagon friction fore is 60N when moving, same for any load its carrying. A horizontal force is applied of 150N causes wagon to be accerate at 5 m/s/s. The same force with a child in the wagon causes it to accerate at 1 m/s/s how do I answer this question to find mass of the child?


Homework Equations



M = F/A


The Attempt at a Solution



First I don't know to find the F in the above equation. I tried doing 150-60 got me 90. So I did the 90/1. Which is 90 kg. But I don't think I did this question correctly as I didnt use 5 at all and the mass of a child cannot be 90 kg. Did I answer it right?


Thanks!
 
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  • #2
homevolend said:
A wagon friction fore is 60N when moving, same for any load its carrying. A horizontal force is applied of 150N causes wagon to be accerate at 5 m/s/s. The same force with a child in the wagon causes it to accerate at 1 m/s/s how do I answer this question to find mass of the child?
[...]
I tried doing 150-60 got me 90. So I did the 90/1. Which is 90 kg.
What, in all, is accelerating in this situation (where the acceleration is 1 [m/s2])? Is it just the child, or the wagon+child?

What's the mass of the wagon?
 
  • #3
homevolend said:

Homework Statement



A wagon friction fore is 60N when moving, same for any load its carrying. A horizontal force is applied of 150N causes wagon to be accerate at 5 m/s/s. The same force with a child in the wagon causes it to accerate at 1 m/s/s how do I answer this question to find mass of the child?


Homework Equations



M = F/A


The Attempt at a Solution



First I don't know to find the F in the above equation. I tried doing 150-60 got me 90.
Yes, that is the NET force, in Newtons.
So I did the 90/1. Which is 90 kg. But I don't think I did this question correctly as I didnt use 5 at all
you should have, instead of using 1. That gives you the mass of the wagon
and the mass of a child cannot be 90 kg. Did I answer it right?


Thanks!
Once you solve for the mass of the wagon, use Newton's 2nd law with the child's mass (M) combined with wagon's mass, to solve for the child's mass.

EDIT: collinsmark beat me to it as I was responding.!
 
Last edited:
  • #4
The 1.0 m/s/s is wagon+child. I have found the mass now of just the wagon. Now to find the mass of the child alone do I take the Fnet and divide it by 1 ? As 1 is the acceration.
 
  • #5
homevolend said:
The 1.0 m/s/s is wagon+child. I have found the mass now of just the wagon. Now to find the mass of the child alone do I take the Fnet and divide it by 1 ? As 1 is the acceration.
Well, if you already know the mass of the wagon+child (together), and you already know the mass of the wagon (by itself), the mass of the child must be ...
 
  • #6
I do not know what it is with the wagon + child together though. I just know what the mass of the wagon by itself is.
 
  • #7
homevolend said:
I do not know what it is with the wagon + child together though. I just know what the mass of the wagon by itself is.
In the case where the wagon is accelerating at 1 [m/s2], the total mass is (mass of wagon + mass of child)

Use Newton's second law to find the mass of wagon+child.

In the case where the wagon is accelerating at 5 [m/s2], the total mass is only the mass of the wagon. You can use Newton's second law again here to find the mass of the wagon.
 
  • #8
K=60N 150-60 = 90N which is the Fnet.
Fa=150N 90/5= 18kg wagon
a1=5m/s/s 90/1= 90kg wagon+child
a2=1 m/s/s

90
- ----- = 72kg child
18

Thanks for helping me answer this question, I guess I didn't fully understand it.

I appreciate it collinsmark:smile:
 

1. What is the friction wagon homework problem?

The friction wagon homework problem is a physics problem that involves calculating the frictional force acting on a wagon as it moves on a surface.

2. Why is it important to solve the friction wagon homework problem?

Solving the friction wagon homework problem allows us to better understand the concept of friction and its effects on moving objects. This knowledge can be applied in real-world situations, such as designing more efficient transportation systems.

3. What are the key factors to consider when solving the friction wagon homework problem?

The key factors to consider are the mass of the wagon, the coefficient of friction between the wagon and the surface, and the angle of the surface the wagon is moving on.

4. What are the steps to solve the friction wagon homework problem?

The first step is to draw a free body diagram of the wagon, showing all the forces acting on it. Then, use Newton's laws of motion to write equations for the forces in the horizontal and vertical directions. Finally, solve for the unknown frictional force using these equations.

5. Are there any real-world applications of the friction wagon homework problem?

Yes, the friction wagon homework problem can be applied in various industries such as transportation, engineering, and manufacturing. It can also help in understanding the braking systems of vehicles and the design of roller coasters.

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