Newton's Law's Problem (Contact Force)

In summary, the masses of the three boxes are M1= 28 kg, M2= 18.7 kg, M3= 28.7 kg, and the applied force on the boxes is 644 N. To find the contact force between M1 and M2, we can use the equation 644/(28 + 18.7) for Part A and 644/(18.7 + 28.7) for Part B. The answers are 13.79 for Part A and 13.58 for Part B. To achieve the correct answer, we can find the acceleration of the total system of three blocks, then take each block apart in a free body diagram and apply Newton's laws. The
  • #1
certainlynot5
3
0
Basically 3 boxes, somehting like this;
05-19alt.gif

Masses are as followed: M1= 28 kg, M2= 18.7 kg, M3= 28.7 kg. The applied force on the box is 644 N

Part A) What is the magnitude of the contact force between M1 and M2
Part B) What is the magnitude of the contact force between M2 and M3


To find the contace force between M1 and M2, i used this equation; 644/(28 + 18.7) for Part A, and 644/(18.7 + 28.7) for Part B. The anwers are; Part A, 13.79, and for Part B, 13.58.

Is this the correct method? If not, what can be done to achieve the correct answer?
 

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  • #2
Start by finding the acceleration of the total system of three blocks. Then take each block apart in a free body diagram, identify all forces acting on each block, and apply Newton's laws.
 
  • #3
and to find acceleration, i would use the formula, F/mg which is 644/28, 644/18.8, 644/28.7?
 
  • #4
certainlynot5 said:
and to find acceleration, i would use the formula, F/mg which is 644/28, 644/18.8, 644/28.7?
No, each block is in contact with each other, so they must each accelertae at the same rate. What is the acceleration of the total system of the 3 blocks together (as if they were one big mass)?
 
  • #5
the the entire mass is 75.4
 
  • #6
certainlynot5 said:
the the entire mass is 75.4
Yes, in kg. So what's the acceleration of the entire mass?
 

FAQ: Newton's Law's Problem (Contact Force)

1. What are Newton's Laws of Motion?

Newton's Laws of Motion are three fundamental principles of physics that describe the behavior of objects in motion. They were first described by Sir Isaac Newton in his book Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) in 1687.

2. What is Newton's Law of Contact Force?

Newton's Law of Contact Force, also known as Newton's Third Law of Motion, states that for every action, there is an equal and opposite reaction. This means that when two objects come into contact, they exert equal but opposite forces on each other.

3. How does Newton's Law of Contact Force apply to everyday life?

Newton's Law of Contact Force can be seen in everyday situations, such as when you push a door open or walk on the ground. When you push on the door, the door pushes back on you with an equal and opposite force, allowing you to move through the doorway. Similarly, when you walk, your feet push against the ground, and the ground pushes back on your feet, propelling you forward.

4. What is an example of Newton's Law of Contact Force in action?

An example of Newton's Law of Contact Force in action is when a person jumps off a diving board. As they push off the board, the board pushes back on them with an equal and opposite force, propelling them into the air. This is also seen in the sport of diving, where divers use this principle to perform flips and twists in the air.

5. How do Newton's Laws of Motion relate to each other?

Newton's Law of Contact Force, along with Newton's First and Second Laws of Motion, work together to describe the behavior of objects in motion. The first law states that an object will remain at rest or in motion with a constant velocity unless acted upon by an external force. The second law relates the force applied to an object to its mass and acceleration. And the third law explains the relationship between forces in a contact situation.

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