Contact Force with two masses given

In summary, the question asked for the contact force between two boxes, one weighing 3.0 kg and the other weighing 5.0 kg, when a horizontal force of 32 N is applied to the 3.0 kg box causing both boxes to slide along a smooth, level floor. Using the equation F=ma, the total mass of 8 kg was found and the acceleration of 4 m/s^2 was calculated. By using F=ma for the 5.0 kg box, the contact force was determined to be 20N.
  • #1
lexikobie
7
1

Homework Statement


A 3.0 kg and a 5.0 kg box rest side by side on a smooth, level floor. A horizontal force of 32 N is applied to the 3.0 kg box pushing it against the 5.0 kg box, and, as a result, both boxes slide along the floor. How large is the contact force between the two boxes?

a) 32N b)24N c) 0N d)20N e) 12N

Homework Equations


F=ma

The Attempt at a Solution


I found the total mass which is 8kg. And then using the F=ma equation, I found my acceleration which is 4 m/s^2. And now...I'm completely stuck on what to do. In class we weren't given an example like this, so I don't know where to go from here...
 
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  • #2
lexikobie said:

Homework Statement


A 3.0 kg and a 5.0 kg box rest side by side on a smooth, level floor. A horizontal force of 32 N is applied to the 3.0 kg box pushing it against the 5.0 kg box, and, as a result, both boxes slide along the floor. How large is the contact force between the two boxes?

a) 32N b)24N c) 0N d)20N e) 12N

Homework Equations


F=ma

The Attempt at a Solution


I found the total mass which is 8kg. And then using the F=ma equation, I found my acceleration which is 4 m/s^2. And now...I'm completely stuck on what to do. In class we weren't given an example like this, so I don't know where to go from here...
Can you show us your free body diagram (FBD) for each of the two boxes? :smile:
 
Last edited:
  • #3
You know mass and acceleration of the 5 kg block.

But I'm not sure if the blocks are really supposed to be frictionless. The answer does not depend on that question, but the points you get for the answer could if there are points for intermediate steps.
 
  • #4
berkeman said:
Can you show us your free body diagram (FBD) for each of the two boxes? :smile:
Yes lol I do but there's no way for me to upload my image from my smartphone since my laptop won't allow me to connect it anymore. Basically I can't upload an image, but I did draw a free body diagram, with two boxes sitting on a horizontal line with the force of 32N being pushed to the right (----->) like this, upon the 3.0kg box. Dunno if that really...explains it, but that's what I drew...
 
  • #5
I finally figured it out! F_2 = m_2 x acceleration. Therefore I get 20 as my answer! Iol I at least appreciate the time you guys used to reply to my question. Many thanks.
 
  • Like
Likes berkeman

FAQ: Contact Force with two masses given

1. What is meant by contact force with two masses given?

Contact force with two masses given refers to the force that two objects exert on each other when they are in physical contact. It is a type of force that is exerted by one object on another through direct contact.

2. How is contact force calculated when two masses are given?

Contact force can be calculated by using the formula F = μN, where F is the contact force, μ is the coefficient of friction, and N is the normal force. This formula takes into account the mass of both objects, as well as the type of surface they are in contact with.

3. What factors affect the magnitude of contact force between two masses?

The magnitude of contact force between two masses is affected by a few factors such as the mass of the objects, the type of surface they are in contact with, and the coefficient of friction between the objects and the surface. Additionally, the angle of the contact surface and any external forces acting on the objects can also affect the magnitude of contact force.

4. Can contact force with two masses given be negative?

Yes, contact force can be negative when the objects are moving away from each other or when there is a decrease in the normal force acting on the objects. In such cases, the contact force is considered to be a resisting force.

5. How does contact force differ from other types of forces?

Contact force differs from other types of forces because it is a result of direct physical contact between two objects. Other types of forces, such as gravitational force or electrostatic force, do not require physical contact between the objects. Additionally, contact force is a short-range force, meaning that it only acts on objects that are in close proximity and in physical contact with each other.

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