Applied force on two blocks on a horizontal frictional plane

In summary, two blocks with masses of 2 kg and 8 kg are connected by a string and pulled across a rough surface by a force applied to the second block at an angle of 52 degrees. The acceleration of gravity is 9.8 m/s2 and each block has an acceleration of 1.6 m/s2 to the right. To find the magnitude of the applied force, you need to draw a free body diagram and sum the forces for each block in the x and y directions. The normal force and the applied force act upward, while the force of gravity acts downward. The tension in the string is what is pulling the second block and can be found by multiplying the mass of the 2 kg block by its
  • #1
lilaznjewel
13
0

Homework Statement


Two blocks connected by a string are pulled
across a rough horizontal surface by a force
applied to one of the blocks.
The acceleration of gravity is 9.8 m/s2 .
1st block = 2 kg
2nd block = 8 kg
Force on second block at 52◦
μ = 0.29

[ 2kg ]-------[ 8kg ]/ 52 degrees

If each block has an acceleration of 1.6 m/s2
to the right, what is the magnitude of the
applied force? Answer in units of N.

Homework Equations


The Attempt at a Solution



What I got was 72.15 N but I got it wrong and I have no idea what I did wrong
 
Last edited:
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  • #2
Draw a fbd and sum the forces for each block in the x and y.
 
  • #3
Jebus_Chris said:
Draw a fbd and sum the forces for each block in the x and y.

what do i use for the force against friction for the block being pulled?
 
  • #4
You need to find an expression for the normal force. In the y direction the force of gravity acts downward, the normal force acts upward, and the applied force acts upward.
 
  • #5
ok for the 8kg block i got 39.30N the problem that i am having for the 2kg block is that i do not no what Force I am solving for that is pulling the block is it Fcos60 like the previous one or is it the tension of the string
 
  • #6
The tension in the string is pulling the second block.
 
  • #7
would you find that simply by multiplying mass times acceleration of the 2kg block?
 
Last edited:

1. What is the relationship between applied force and acceleration for two blocks on a horizontal frictional plane?

The relationship between applied force and acceleration for two blocks on a horizontal frictional plane is described by Newton's Second Law of Motion. This law states that the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. In this scenario, the net force is equal to the applied force minus the force of friction, and the acceleration is shared by both blocks.

2. How does the coefficient of friction affect the motion of two blocks on a horizontal plane?

The coefficient of friction is a measure of the force of friction between two surfaces in contact. In the case of two blocks on a horizontal plane, a higher coefficient of friction will result in a greater force opposing the motion of the blocks. This means that a higher coefficient of friction will require a greater applied force to overcome and produce the same acceleration as a lower coefficient of friction.

3. How does the mass of the blocks affect the motion on a horizontal frictional plane?

The mass of the blocks affects the motion on a horizontal frictional plane because it is a factor in determining the acceleration of the blocks. As mentioned before, according to Newton's Second Law of Motion, the acceleration is inversely proportional to the mass. This means that a greater mass will result in a smaller acceleration for the same applied force.

4. Can the direction of the applied force affect the motion of two blocks on a horizontal frictional plane?

Yes, the direction of the applied force can affect the motion of two blocks on a horizontal frictional plane. The magnitude and direction of the applied force will determine the net force acting on the blocks, which will in turn affect their acceleration. For example, if the applied force is directed at an angle to the plane, it will have both horizontal and vertical components that will contribute to the motion of the blocks.

5. How does the presence of external forces, such as air resistance, affect the motion of two blocks on a horizontal frictional plane?

The presence of external forces, such as air resistance, can affect the motion of two blocks on a horizontal frictional plane. These external forces will add to the net force acting on the blocks and can either increase or decrease their acceleration depending on their direction. For example, air resistance will oppose the motion of the blocks and decrease their acceleration. It is important to take into account all external forces when analyzing the motion of objects on a horizontal frictional plane.

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